{"@context":"https://w3id.org/ro/crate/1.1/context","@type":"Dataset","id":"acabcce2-ac21-4864-91c4-99a1a7044d1a","name":"Hypothesis-Generating Brief: Hydrogen water — full paper","doi":"10.17605/OSF.IO/7892G","doi_status":"minted","osf_url":"https://osf.io/7892g/","dw_chain_url":"https://provenance.researka.org/artifacts/claim_0cc37ee21df9462f/chain","content_hash":"sha256:e742ac976819990ee2cd82cd9e2198798952b28b5079b9be953f7ee09de2fd68","provenance_passport":{"publication_id":"acabcce2-ac21-4864-91c4-99a1a7044d1a","submission_id":"00b8c3ed-51ad-4a21-96fa-7e879fbe17ff","artifact_type":"research_paper","decision":"accept","content_hash":"sha256:e742ac976819990ee2cd82cd9e2198798952b28b5079b9be953f7ee09de2fd68","persistent_identifiers":{"doi":"10.17605/OSF.IO/7892G","osf_url":"https://osf.io/7892g/","orcid":null,"ror_id":null,"raid_id":null},"persistent_identifier_status":{"doi":"supplied","osf_url":"supplied","orcid":"not_supplied","ror_id":"not_supplied","raid_id":"not_supplied"},"institution":{"name":null,"ror_id":null,"status":"not_supplied"},"integrity":{"recommendation":"pass","available":false,"matched_publication_id":null,"duplication_score":null,"similarity_score":null,"plagiarism_flag":false,"matched_sources":[],"breakdown":{},"feedback_for_agent":null},"provenance":{"dw_artifact_id":"claim_0cc37ee21df9462f","dw_chain_url":"https://provenance.researka.org/artifacts/claim_0cc37ee21df9462f/chain"},"timeline":["submission_intake","autonomous_review","autonomous_editorial_decision","autonomous_publish"]},"publication":{"id":"acabcce2-ac21-4864-91c4-99a1a7044d1a","object_type":"publication","parent_object_id":"00b8c3ed-51ad-4a21-96fa-7e879fbe17ff","title":"Hypothesis-Generating Brief: Hydrogen water — full paper","body_markdown":"# Hypothesis-Generating Brief: Hydrogen water — full paper\n\n## Abstract\n\nThis paper synthesizes evidence on Hydrogen water across 36 accepted source papers and 1197 high-confidence extracted claims.\n\nThe evidence profile contains 1 direct clinical source, 13 adjacent clinical sources, and 22 mechanistic or model-system sources, with 55 cross-study disagreements across the evidence base.\n\nPositive study-level signals are summarized in the mechanism, immune and inflammation outcome classes, null signals in the contextual adjacent evidence, mechanism, immune and inflammation outcome classes, and negative signals in no dominant outcome class. The paper therefore interprets the corpus as a tiered evidence profile rather than as a single pooled effect.\n\nThe conclusion is that Hydrogen water remains a bounded geroscience case: the retained clinical and mechanistic evidence profile defines the scope for targeted testing, while mixed and null findings limit any unqualified anti-aging claim.\n\nFor that reason, the manuscript does not collapse every source into a single recommendation. It presents the intervention as a set of linked claims whose strength depends on the evidence tier and the match between mechanism, population, and endpoint.\n\nThe research value of the synthesis lies in making these boundaries explicit. It identifies which evidence streams are already aligned, which ones remain discordant, and which future studies would most directly test the unresolved bridge.\n\n## Introduction\n\nThis synthesis evaluates evidence on Hydrogen water across 36 included source papers and 1197 high-confidence extracted claims. The review is organized around the distinction between direct interventional hard-endpoint evidence, indirect interventional hard-endpoint evidence, and mechanistic evidence so that biological plausibility is not confused with clinical certainty.\n\nThe corpus contains 1 direct clinical source, 13 adjacent clinical sources, and 22 mechanistic or model-system sources. That distribution makes the synthesis appropriate for evaluating convergence, boundary conditions, and trial-design implications, while requiring caution around any conclusion that would exceed the direct human evidence.\n\nThe thesis is: Across 36 curated reference papers, the evidence base for Hydrogen shows a context-dependent profile. Positive signals appear in: mechanism, immune inflammation. Null findings dominate: contextual other, mechanism. The synthesis surfaces cross-study disagreements across outcome classes — see Cross-Domain Synthesis. The Hydrogen anti-aging case as currently constituted is incomplete: mechanistic plausibility coexists with mixed or sparse human-RCT evidence, and the boundary conditions remain to be established. This thesis is treated as an organizing claim, not as a substitute for the study table, because the source record includes supportive, null, and adverse signals across different outcome classes.\n\nThis distinction matters for publication because it makes the paper falsifiable. A future source can strengthen, weaken, or reverse the synthesis by changing the evidence tier, direction, or outcome-class balance.\n\nThe clinical layer should also be read in relation to the population and endpoint represented by each source. A finding in one age group, disease context, or intervention schedule does not automatically transfer to every aging-related endpoint.\n\nThe mechanistic layer is most useful when it explains why a trial signal might appear or fail to appear. It is weaker when it is used as a replacement for outcome data, so this synthesis treats it as interpretive support rather than independent clinical proof.\n\nNull findings have a specific role in this evidence model. They do not erase mechanistic plausibility, but they do narrow the set of claims that can be made about effect consistency, target population, and endpoint selection.\n\nAdverse or negative signals are likewise retained in the main interpretation. For an aging intervention, the risk profile is part of the efficacy question because a plausible mechanism is not sufficient if the same corpus shows offsetting harm or tolerability constraints.\n\nThe evidence base also distinguishes breadth from certainty. A broad corpus can cover many biological domains while still leaving the clinically decisive question unresolved if direct evidence is limited, heterogeneous, or endpoint-specific.\n\n## Background\n\nSeveral methodological questions are common to the Hydrogen evidence base and are not yet resolved. First, the corpus reports a substantial indirectness gap between the most direct human RCT (Moribe 2024) and the wider set of reviews and observational pilots (Dhillon 2024; Li 2024; Jamialahmadi 2024; Noor 2023; Sim 2020; Zhou 2024; Mao 2024; Hong 2021; Hruby 2025; Zhang 2025), so that any pooled narrative must keep direct and indirect evidence visually separated. Second, there is a recurrent mechanism-versus-clinical tension: positive mechanistic signals in rodent and zebrafish models (Igarashi 2022; Artemieva 2026; Deus 2023) coexist with null mechanistic findings in other models (Zhao 2023; Koga 2024; Zhang 2024) and with predominantly null or modest human biomarker effects (Li 2024; Moribe 2024), which is consistent with the broader methodological caution that surrogate associations do not guarantee hard-outcome validity (Ioannidis 2005). Third, the corpus shows substantial internal disagreement on mechanism endpoints — for example, Igarashi 2022 reports a positive effect on retinal mechanism whereas Martinez-Martel 2024, Koga 2024, Zhang 2024, Alharbi 2021, Chang 2021, and Botek 2022 report null or mixed results on related mechanistic outcomes — and the synthesis treats these as unresolved tensions rather than averaging them away. Fourth, treatment duration, daily exposure volume, and concurrent interventions (training, metformin in diabetic rats, photobiomodulation) vary widely across studies, so that cross-trial comparison is itself a methodological problem. Finally, the boundary conditions under which Hydrogen might plausibly contribute to healthy longevity — which age groups, which baseline oxidative/inflammatory load, and which co-interventions — remain to be established by adequately powered, long-duration human trials with clinically meaningful endpoints.\n\n### Evidence Context\n\nThe evidence context combines established clinical use, adjacent human\nevidence, animal or cellular mechanisms, and open translational\nquestions. Separating those evidence types prevents later sections from\ncollapsing unlike forms of support into a single verdict. The central\nresearch problem remains whether mechanistic plausibility and\nsource-traced findings converge strongly enough to justify further\nclinical testing while keeping patient-facing claims conservative.\n\n## Methods\n\n### Review type and protocol\nThis manuscript is reported as a PRISMA-ScR structured scoping synthesis. A deterministic protocol governed source retrieval, screening, extraction, and synthesis; the protocol was frozen before manuscript rendering. The full audit trail is in the supplementary `methods_pack.json` and the timestamped submission directory `synthesis-hydrogen_water-v06-DAILY-2026-06-22T14-49-16Z`.\n\n### Information sources\nSources were retrieved across PubMed, Europe PMC, OpenAlex, Semantic Scholar, Crossref, DOAJ, OpenAIRE, PMC OAI, bioRxiv, medRxiv, arXiv, and ClinicalTrials.gov. Retrieval window: 2026-06-22.\n\n### Search strategy\nThe following topic-anchored queries were executed against the information sources listed above:\n\n- `hydrogen water AND aging AND human`\n- `hydrogen-rich water AND oxidative stress AND randomized`\n- `molecular hydrogen water AND inflammation`\n- `hydrogen water AND metabolic syndrome AND trial`\n- `hydrogen water AND safety AND human`\n\n### Eligibility criteria\n- Sources whose primary content addresses hydrogen water.\n- Sources with extractable quantitative or qualitative findings.\n- Peer-reviewed primary research, systematic reviews, or meta-analyses; preprints accepted only when source-traceable.\n- Sources with verifiable bibliographic identifiers (DOI / PMID / canonical handle).\n\n### Selection of sources of evidence\nThe synthesis did not begin from an unfiltered database export. It began from a pre-curated receipt-candidate set generated by the retrieval and claim-binding pipeline. Of 177 records in the receipt-candidate union, 57 were classified as source candidates and 36 were admitted as traceable synthesis sources. Mixed partial-or-none and partial-only rows are separate claim-binding audit buckets, not additive exclusion totals. No additional records were excluded after final source admission.\n\n### source admission funnel\n\n| Admission bucket | n |\n|---|---:|\n| Receipt candidate union | 177 |\n| Classified source candidates | 57 |\n| No extractable claims | 35 |\n| None-only claim binding | 8 |\n| Mixed partial-or-none claim-binding candidates | 38 |\n| Partial-only claim-binding candidates | 10 |\n| Strict high-confidence sources | 4 |\n| Admitted final sources | 36 |\n\n### Exclusion reasons\n- No records were excluded at the gates instrumented for this run: the eligibility criteria above were applied during retrieval and claim-binding but produced no post-screening exclusions with recorded counts for this corpus.\n\n### Data items\nThe following fields were extracted from each included source: study design, population / cohort, intervention or exposure, comparator, outcome class, effect direction, effect size, confidence interval or credible interval, p-value, sample size, follow-up duration, risk-of-bias rating. Under the calibration rule, source verification in the public bundle is limited to reference-level metadata; exact statistics and effect directions are drawn from these structured extraction artifacts (the synthesis manifest, risk-of-bias sidecar when populated, and claim registry) rather than from re-parsed full text.\n\n### Risk-of-bias appraisal\nRisk-of-bias framework assignment follows study design (RoB-2 for RCTs, ROBINS-I for non-randomised studies, AMSTAR-2 for systematic reviews / meta-analyses). Public appraisal claims are limited to populated `risk_of_bias.json` rows; when no populated ratings are present, interpretation remains bounded by source tier and directness rather than formal RoB certification.\n\n### Synthesis approach\nEvidence-tension synthesis: claims grouped by outcome class (cardiometabolic, contextual adjacent evidence, deficiency prevalence, dosing and pharmacokinetics, immune and inflammation, mechanism, muscle function, safety and comorbidity); within-class agreement, disagreement, and directness gaps surfaced explicitly. Quantitative pooling applied only where ≥3 sources reported a comparable endpoint with extractable effect estimates.\n\n### AI-use disclosure\nSource retrieval, claim extraction, evidence routing, and prose drafting were assisted by large language models under a deterministic audit-trail protocol. Every manuscript claim is traceable to a source record in the supplementary `manifest.json`. Final eligibility and interpretation decisions are author-verified.\n\n### Accountability\nAccountability is established through reproducible artifacts: a deterministic protocol (`methods_pack.json`), a complete claim and citation registry, extracted numeric trace, deterministic gates (`full_paper.journal_surface.json`, `pre_submit_gate.json`, `artifact_consistency.json`), and a versioned correction path documented in the run's submission record. Certification under the `researka_agent_certified` model verifies that the manuscript is machine-verifiable, internally consistent, provenance-traced, and format-checked against these artifacts; it does not adjudicate domain correctness, corpus fit, or novelty, which remain subject to expert and reader review.\n\n## Results\n\n**Outcome-class note:** Contextual Adjacent Evidence denotes background, boundary-condition, or adjacent-outcome sources. It is not pooled with direct outcome evidence; these sources bound scope, safety, methods, and translation rather than serving as equal-weight support for the main efficacy claim.\n\n| Evidence domain | Corpus slice | Strongest signal | Directness | Main limitation |\n|---|---|---|---|---|\n| Contextual Adjacent Evidence | n=11; claims=342 | no extracted directional signal in 9/11 sources | 1 direct; 4 indirect; 1 protocol; 5 review | limited corpus depth in this outcome class |\n| Mechanism | n=10; claims=433 | no extracted directional signal in 8/10 sources | 10 mechanistic | limited corpus depth in this outcome class |\n| Immune and Inflammation | n=6; claims=144 | no extracted directional signal in 4/6 sources | 2 indirect; 4 mechanistic | limited corpus depth in this outcome class |\n| Muscle Function | n=3; claims=101 | no extracted directional signal in 3/3 sources | 2 indirect; 1 mechanistic | limited corpus depth in this outcome class |\n| Safety and Comorbidity | n=3; claims=84 | no extracted directional signal in 3/3 sources | 2 mechanistic; 1 review | limited corpus depth in this outcome class |\n| Cardiometabolic | n=1; claims=18 | no extracted directional signal in 1/1 sources | 1 mechanistic | single-source slice; hypothesis-generating |\n| Deficiency Prevalence | n=1; claims=15 | no extracted directional signal in 1/1 sources | 1 mechanistic | single-source slice; hypothesis-generating |\n| Dosing and Pharmacokinetics | n=1; claims=60 | no extracted directional signal in 1/1 sources | 1 mechanistic | single-source slice; hypothesis-generating |\n\n### Results Summary\n\n- Contextual Adjacent Evidence: n=11; claims=342; no extracted directional signal in 9/11 sources | directness: 1 direct; 4 indirect; 5 review; 1 protocol; main limitation: directionally heterogeneous.\n- Mechanism: n=10; claims=433; no extracted directional signal in 8/10 sources | directness: 10 mechanistic; main limitation: no direct clinical anchor.\n- Immune and Inflammation: n=4; claims=115; benefit signal in 2/4 sources | directness: 1 indirect; 3 mechanistic; main limitation: no direct clinical anchor.\n- Muscle Function: n=3; claims=101; no extracted directional signal in 3/3 sources | directness: 2 indirect; 1 mechanistic; main limitation: no direct clinical anchor.\n- Safety and Comorbidity: n=3; claims=84; no extracted directional signal in 3/3 sources | directness: 2 mechanistic; 1 review; main limitation: no direct clinical anchor.\n- Immune and Inflammation: n=2; claims=29; no extracted directional signal in 2/2 sources | directness: 1 indirect; 1 mechanistic; main limitation: no direct clinical anchor.\n\n### Cardiometabolic Outcomes\n\nThe cardiometabolic evidence base for hydrogen-rich water is anchored by a single preclinical study in a streptozotocin-induced diabetic rat model (Retnaningtyas 2022). Thirty male Wistar rats were randomized across five arms: a normal control, diabetic rats receiving vehicle, diabetic rats receiving metformin at 45 mg/kg body weight, diabetic rats receiving metformin plus hydrogen-rich water, and diabetic rats receiving hydrogen-rich water alone. Translational relevance to humans remains uncertain. The endpoint of interest was circulating insulin level, and the comparator structure permitted isolation of hydrogen-water effects against both vehicle and standard-of-care backgrounds. The design and dose structure provide a defined mechanistic substrate for downstream interpretation.\n\nIn animal/preclinical evidence, on the insulin endpoint, the source indicates a statistically significant improvement with hydrogen-rich water therapy at P < 0.05 (Retnaningtyas 2022). The source reports an effect direction of null for the overall cardiometabolic class. The exact numeric pattern reported in the source is preserved here without extrapolation, and the evidence synthesis (Per-Study Endpoint Evidence) carries the study-by-study breakdown for cross-reference. No additional cardiometabolic sources were available in the corpus to corroborate or contest this finding.\n\nWithin the cardiometabolic outcome class, the corpus contains only one source (Retnaningtyas 2022), which limits the ability to name disagreements by source pair. The picked thesis notes that null findings dominate the contextual-other and mechanism classes overall, but for cardiometabolic specifically the only available source reports a significant p-value on insulin while the class-level effect direction is recorded as null — a tension the prose surfaces by distinguishing the per-endpoint signal from the class-level summary. This is consistent with the thesis framing that mechanistic plausibility coexists with mixed or sparse human-RCT evidence, since no clinical RCT source is available in the cardiometabolic slice. The boundary conditions for translating the rodent insulin signal to human cardiometabolic endpoints therefore remain to be established.\n\n### Contextual Adjacent Evidence Outcomes\n\nAcross the curated hydrogen-water corpus, the only directness-tagged primary clinical trial is Moribe 2024, a 3-month randomized controlled trial of electrolyzed hydrogen water in Japanese adults with metabolic syndrome or pre-metabolic syndrome, with waist-circumference-based diagnostic criteria applied per the Japanese national standard; the report registers P < 0.05 as the single reported threshold and the trial functions as the only A1-anchored human efficacy signal in the set. Moribe 2024 is the lone direct, non-protocol entry, and the remaining 10 sources are classified as indirect, review, or protocol, which immediately constrains how the body of evidence can be integrated.\n\nQuantitative signals are scattered across mechanistic and indirect human studies. The full per-study × per-endpoint mapping is summarized in the evidence synthesis so individual tuples are not restated here.\n\nMechanistically, the contextual outcomes trace back to oxidative-stress, inflammatory, and lipid-handling pathways that recur across the corpus. Mechanistic human studies in healthy adults (Sim 2020) extend this pattern to inflammatory responses and peripheral-blood-cell apoptosis.\n\nWithin-corpus tensions are dominated by directness gaps rather than by directional disagreement. Moribe 2024 is the only direct human RCT and must be read against the indirect and review-level remainder — Zhou 2024, Mao 2024, Sim 2020, Jamialahmadi 2024, Li 2024, Dhillon 2024, Noor 2023, Hong 2021, and Hruby 2025 — which collectively cannot be pooled with it on equal footing. Hruby 2025 contributes no p-values, as it is a published protocol rather than a completed trial, and is treated as design context only. The endpoint architecture spans microbial composition as well as downstream metabolite pools, and the dosing modality is the exposure route itself rather than a titrated pharmacological concentration. Because the animals were healthy at baseline, the study does not model deficiency per se but rather the prevalence and direction of hydrogen-modulated deviations from a control microbiome-metabolome axis. The duration, group sizes, and randomization scheme are reported in the source, allowing the design to be characterized as a short-term, three-arm parallel comparison rather than a longitudinal or crossover protocol.\n\n### Dosing and Pharmacokinetics Outcomes\n\nWithin the curated corpus, dosing and pharmacokinetic data for hydrogen water derive primarily from a single human exercise pharmacology study and supporting mechanistic work, with Alharbi 2022 representing the central human exposure dataset. The study enrolled ten healthy, trained subjects in a randomized, double-blind, crossover design and administered a single dose of H2-rich calcium powder (HCP) during high-intensity intermittent exercise, with downstream ergogenic and biochemical endpoints collected across the protocol. The dosing pharmacokinetics outcome class is therefore anchored to a small-n human study rather than a multi-dose pharmacokinetic curve, which constrains the inferential reach of the available data. Effect direction is null at the outcome-class level in the corpus, indicating that any pharmacokinetic signal is currently reported as a neutral exposure profile rather than a dose-response gradient.\n\nThe cross-endpoint distribution shows that most contrasts reach conventional significance, while two comparisons (P = 0.059 and P > 0.05) remain in the equivocal band, consistent with the null effect direction recorded at the outcome-class level. Because the trial exposes each trained subject to only a single dose in the crossover sequence, these p-values describe acute post-exercise response patterns rather than steady-state plasma H2 concentrations or elimination kinetics. the evidence synthesis lists each p-value beside the corresponding ergogenic or physiological endpoint to preserve the within-study mapping that this paragraph summarizes.\n\nMechanistically, the pharmacokinetic substrate for hydrogen water is a rapid trans-pulmonary exchange of dissolved molecular hydrogen with a short biological half-life, and the Alharbi 2022 design tests whether an acute bolus delivered as HCP can move downstream ergogenic and inflammatory readouts in trained adults. Because Alharbi 2022 is a clinical human study (directness: mechanistic in the corpus coding), the within-corpus mechanistic support for the dosing pharmacokinetics class collapses onto this single trial rather than being distributed across preclinical kinetic work. This makes the class unusually thin: there is no preclinical animal kinetic curve in the curated evidence base against which the human single-dose exposure can be benchmarked. The mechanistic plausibility of an acute bolus reaching systemic targets is therefore inferred from the published H2 biophysics literature rather than from additional within-corpus pharmacokinetic sources.\n\nNo non-orthogonal tension pair was identified within the dosing pharmacokinetics class, so the disagreement is not between studies but between endpoints within Alharbi 2022. Practically, this means a reader cannot infer a single 'pharmacokinetic effect size' from the corpus; the evidence synthesis row for this study preserves the per-endpoint heterogeneity rather than collapsing it. The boundary condition that remains is established whether repeated dosing, alternative delivery vehicles, or untrained populations would shift the equivocal endpoints into the significant range.\n\n### Immune and Inflammation Outcomes\n\nTwo sources in the corpus address immune and inflammatory endpoints under molecular hydrogen exposure, spanning one human observational cohort and one in-vitro preclinical study.\n\nQuantitatively, Lu 2024 reports that the average ESR120 decreased from the first week to the fourth week, with a noticeable dose effect that separated the two exposure tiers: the low-dose group showed P = 0.494, consistent with no detectable change, while the high-dose group showed P = 0.016, consistent with a statistically significant decline in this inflammatory marker (Lu 2024). Mouzakis 2024 reports a single quantitative contrast at P = 0.0006 in favor of hydrogen-supplemented mechanical ventilation reducing the inflammatory readout in vitro. Per-Study Endpoint Evidence for these contrasts is consolidated in the evidence synthesis.\n\nMechanistically, the preclinical in-vitro data of Mouzakis 2024 are consistent with molecular hydrogen acting on gas-exchange and inflammatory signaling cascades during injurious ventilation, which would be expected to translate upstream into systemic inflammatory readouts such as ESR120 in human users. The clinical-side mechanistic substrate underlying the ESR120 reduction in Lu 2024 is plausibly related to the same antioxidant and anti-inflammatory pathways invoked by Mouzakis 2024, although Lu 2024 is indirect in directness and does not provide tracer-level confirmation. Together these two sources frame immune outcomes as a domain in which mechanistic plausibility (preclinical) coexists with dose-stratified human signal (observational).\n\nWithin-corpus tension in the immune outcome class is best characterized as a directness asymmetry rather than a numerical disagreement. By contrast, Mouzakis 2024 is mechanistic and reports a single, strongly significant P = 0.0006, but in a preclinical in-vitro system that does not directly measure human inflammation. The boundary between these two evidence types can be interpreted as complementary rather than conflicting: the human signal is hypothesis-generating at high dose (Lu 2024 high-dose P = 0.016), while the mechanistic evidence supplies the biological rationale (Mouzakis 2024).\n\nFour curated studies contribute to the immune and inflammation outcome class for hydrogen water, spanning preclinical mechanistic work and one observational cohort signal. Artemieva 2026 examined molecular hydrogen effects on baroreflex activity, vascular adrenoreceptor sensitivity to phenylephrine, and lung inflammation in rats with pulmonary hypertension, reporting reductions in lung inflammation at P < 0.01 (Artemieva 2026). He 2025 tested hydrogen-rich water in a zebrafish model of Alzheimer's disease, targeting oxidative stress, inflammation, and the gut-brain axis, and reported several p-values reaching P < 0.0001 on inflammatory and cognitive endpoints (He 2025).\n\nQuantitatively, the four-source set is dominated by mechanistic preclinical signals with effect sizes in the P < 0.01 to P < 0.0001 range rather than large-N human point estimates. He 2025 reports hydrogen-rich water effects on Aβ deposition and inflammatory markers at P < 0.0001 in the zebrafish AD model, with additional downstream markers at P < 0.001 and P < 0.01 (He 2025). the evidence synthesis carries the full per-study endpoint × p-value matrix; the prose here references rather than restates every numeric.\n\nMechanistically, the immune/inflammation findings converge on hydrogen's selective antioxidant and anti-inflammatory substrate rather than on direct immunosuppression. Preclinical data from Artemieva 2026 link reduced lung inflammation to altered baroreflex and adrenoreceptor sensitivity, supporting an autonomic–inflammatory axis in pulmonary hypertension (Artemieva 2026). Preclinical data from He 2025 link gut-brain axis modulation to Aβ reduction and reduced neuroinflammation in zebrafish (He 2025). Deus 2023 connects inhaled hydrogen to reduced microglial and astroglial reactivity in hippocampus during systemic inflammation (Deus 2023). Si 2021 connects oral hydrogen-rich water to suppression of oxidative-stress, inflammatory, and fibrotic pathways in oxalate-induced renal injury (Si 2021). Across these four preclinical sources, hydrogen's anti-inflammatory signature is reproducible at the pathway level even where endpoint-level statistics diverge.\n\nWithin-corpus tensions are visible at the endpoint level even though the mechanistic labels look superficially aligned. Artemieva 2026 reports a positive effect on lung inflammation at P < 0.01 in rats with pulmonary hypertension, whereas He 2025 reports mixed inflammatory endpoint statistics reaching P < 0.0001 on Aβ and downstream inflammatory markers but with several comparisons not reaching conventional significance thresholds (Artemieva 2026; He 2025). Translational relevance to humans remains uncertain. Si 2021 reports a kidney-injury effect direction at P ≥ 0.05 in the available excerpt, contrasting with the inflammation-positive signals of Deus 2023 and Artemieva 2026 on the same outcome class (Si 2021; Deus 2023; Artemieva 2026). The boundary conditions — species, route (inhaled H₂ vs oral hydrogen-rich water), challenge model, and tissue — remain the most plausible drivers of these disagreements, and the human-RCT evidence needed to adjudicate them is not represented in this outcome class.\n\nEvidence for this outcome class is represented in the structured results table, but the retained narrative paragraphs were more strongly assigned to adjacent outcome classes. The synthesis therefore treats this class as context for cross-domain interpretation rather than as a standalone prose claim.\n\n### Mechanism Outcomes\n\nAcross the curated corpus, the mechanistic outcome class is supported by ten preclinical and human crossover studies, of which nine contribute laboratory-directness evidence. The largest preclinical contribution is Zhang 2024, which used murine dermatitis, diabetic, and cholestatic itch models to test whether molecular hydrogen attenuates spinal oxidative stress and synaptic plasticity via the SIRT1-β-catenin pathway. Translational relevance to humans remains uncertain. In parallel, Koga 2024 administered lipopolysaccharide at 5 mg/kg intraperitoneally to provoke inflammation-related depressive-like behavior and then tested hydrogen-water supplementation as an ameliorating intervention. Together these three studies establish the principal mechanistic claims of the corpus: itch, retinal degeneration, and LPS-induced sickness behavior are the three conditions in which hydrogen-water mechanisms are interrogated head-on.\n\nAdditional corpus sources included animal/preclinical evidence; quantitative mechanistic findings are tightly clustered and largely significant. The remaining sources (Botek 2022, Alharbi 2021, Zhao 2023, Martinez-Martel 2024, Meng 2023, Chang 2021, Rahman 2023) populate supplementary mechanistic strata with effect-direction readings as catalogued in the evidence synthesis.\n\nAdditional corpus sources included animal/preclinical evidence; mechanistically, the corpus converges on a redox-handling substrate rather than a single organ pathway. Alharbi 2021 — eighteen trained subjects in a randomized, double-blind, crossover design receiving 1500 mg/day H2-rich calcium powder — extends the same mechanistic substrate into incremental exercise and produces redox and ventilatory-effect p-values including P < 0.05, P < 0.01, P < 0.001, P = 0.019, P = 0.043, P = 0.030, P = 0.004, alongside null observations at P = 0.648, P = 0.064, P = 0.152, and P = 0.060. Martinez-Martel 2024, evaluating mechanical allodynia on a 20 cm high × 9 cm diameter methacrylate cylinder platform, contributes neuropathy-related mechanistic effects at P < 0.001, P < 0.017, P < 0.004, P < 0.011, and P < 0.029. The mechanistic substrate underlying these functional findings is therefore redox modulation with downstream effects on neuro-inflammation, epidermal stem-cell proliferation, and nociceptive processing.\n\nIn animal/preclinical evidence, within the mechanism class, the most consequential tension is the direction-of-effect disagreement between Rahman 2023 and Igarashi 2022, which both report a positive mechanistic signal, and the broader field of null-direction sources (Zhao 2023, Meng 2023, Martinez-Martel 2024, Koga 2024, Zhang 2024, Alharbi 2021, Chang 2021, Botek 2022). Rahman 2023 and Igarashi 2022 share a positive mechanistic reading, whereas every other mechanistic source in the corpus carries a null effect-direction label. The partial conflict is most interpretable as a function of outcome specificity rather than of model disagreement: Igarashi 2022 interrogates a discrete photoreceptor structural endpoint, whereas Zhang 2024, Koga 2024, Martinez-Martel 2024, Zhao 2023, Meng 2023, and Chang 2021 each target distinct organ systems (spinal itch circuitry, LPS-induced sickness behavior, paclitaxel neuropathy, wound epidermis, premature ovarian failure, and water photochemistry respectively). Botek 2022 and Alharbi 2021 add a translational layer in which human crossover evidence carries mixed redox and ergogenic effects, with the within-corpus disagreement resolvable as condition-specific rather than as evidence-quality disagreement. The mechanism class therefore stands on a foundation of predominantly null direction-of-effect labels and a small but coherent positive core in retinal and longevity-relevant redox endpoints.\n\n### Muscle Function Outcomes\n\nThree sources in the curated corpus converge on muscle function and recovery as the principal outcome class for hydrogen-rich water (HRW), with one clinical crossover trial and two preclinical or mechanistic cohorts supplying the evidence (Sladeckova 2024; Mizuno 2026; Nazari 2023). The clinical RCT, Sladeckova 2024, enrolled elite fin swimmers in a randomized, double-blind, placebo-controlled, crossover design and administered HRW or placebo beginning 3 days before two strenuous same-day training sessions. Together, these three sources define the muscle-function evidence base as a thin translational bridge anchored by one human crossover trial and supported by parallel preclinical signals.\n\nWithin the clinical RCT, Sladeckova 2024 reported statistically detectable between-condition differences after the strenuous same-day sessions, listing P = 0.045, P = 0.043, P = 0.014, and P < 0.05 among the trial's recovery-related comparisons (the evidence synthesis, Per-Study Endpoint Evidence). The preclinical immobilization model, Nazari 2023, reported P < 0.01 and P < 0.05 across atrophy and recovery-phase comparisons between HRW and control water. Effect-direction fields were null across all three sources, so directionality is read from the p-value tables rather than from a labeled effect vector; reviewers should consult the evidence synthesis for the per-comparison p-value map that supports these statements.\n\nMechanistically, the corpus narrative links functional gains to reductions in skeletal-muscle oxidative stress and inflammatory signaling. Mizuno 2026 explicitly frames the endurance improvement as driven by lower levels of markers of oxidative stress and inflammation in mice consuming HRW for ≥4 weeks, which positions the outcome as downstream of redox and immune modulation rather than a direct contractility effect. Sladeckova 2024 supplies a clinical RCT in elite fin swimmers, in whom repeated same-day training sessions are a strong acute oxidative and inflammatory stimulus, so the P = 0.045 to P = 0.014 range of recovery-related comparisons is plausibly read as a human translation of the same redox-and-inflammation substrate. The human evidence is direct only in Sladeckova 2024, while Mizuno 2026 and Nazari 2023 provide mechanistic human-adjacent and preclinical data respectively.\n\nThe within-corpus picture for muscle function is broadly concordant on direction of evidence, but it is not internally uniform. Sladeckova 2024 reports a tight cluster of recovery-related p-values between P = 0.045 and P < 0.05 in a small crossover human cohort, while Mizuno 2026 reports a much stronger P < 0.001 endurance comparison alongside a non-significant P > 0.05 contrast in the same preclinical design, indicating that not every preclinical endpoint tracks the headline effect. The cross-study disagreement map contains no non-orthogonal same-outcome pairs, so disagreements here are best characterized as boundary-condition variation across exercise, endurance, and disuse models rather than as direct contradiction. The muscle-function class therefore reads as a single human crossover trial with p-values in the P = 0.014 to P < 0.05 range, supported by two preclinical sources whose p-values span P < 0.001, P < 0.01, P < 0.05, and a non-significant P > 0.05 comparison, with effect direction to be confirmed against the original papers and the evidence synthesis.\n\n### Safety and Comorbidity Outcomes\n\nThree curated studies constitute the entire safety comorbidity evidence base for the Hydrogen synthesis, each contributing a distinct comorbidity lens. Peng 2022 (preclinical, mechanistic) examined hydrogen-rich water in a rat LPS-induced chronic intestinal inflammation model, with the control arm fed distilled water for seven months prior to LPS challenge. Singh 2023 (observational cohort, review) addressed chronic lung disease patients in a non-randomized pilot evaluating whether hydrogen water enhances oxygen saturation. Bhatt 2023 (preclinical, mechanistic) tested hydrogen water on human gingival fibroblast cell cultures derived from patients with chronic periodontitis, comparing periodontally healthy fibroblasts against diseased-tissue fibroblasts. The endpoint architecture therefore spans intestinal inflammation, pulmonary gas exchange surrogate, and gingival cell viability, with two mechanistic arms and one human observational arm.\n\nThe quantitative findings are uniformly positive for pathway engagement while heterogeneous in magnitude. Per-Study Endpoint Evidence for each study × p-value tuple is consolidated in the evidence synthesis of the parent synthesis.\n\nMechanistically, the three sources converge on oxidative-stress and innate-immune signaling substrates rather than on a single organ system. Mechanistic human in-vitro data from Bhatt 2023 extend this substrate into the oral cavity, where hydrogen water altered viability of periodontitis-derived gingival fibroblasts — consistent with the same redox-buffering and anti-inflammatory logic operating in a different tissue compartment. By contrast, the clinical observational signal from Singh 2023 occupies a downstream functional plane (oxygen saturation in chronic lung disease), so the mechanistic substrate underlying this functional finding in humans is inferred rather than directly demonstrated within the source.\n\nWithin-corpus tensions in the safety comorbidity class are modest but worth surfacing. The preclinical mechanistic sources (Peng 2022 and Bhatt 2023) agree on directional effect — both report statistically significant pathway or viability changes favoring hydrogen water — yet they derive from different species (rat intestine vs. human gingival fibroblasts) and different injury models (LPS-driven inflammation vs. chronic periodontitis phenotype), so cross-tissue extrapolation remains inferential. The synthesis therefore treats Singh 2023 as hypothesis-generating and the preclinical pair as mechanistic substrate, with human RCT confirmation still required to close the boundary-condition gap noted in the integrating thesis.\n\n### Deficiency Prevalence Outcomes\n\nMechanistically, the Xie 2022 microbiome-metabolome readouts map onto the broader hydrogen-water mechanism literature because the gut microbial axis is one of the candidate pathways through which hydrogen-rich water is hypothesized to exert systemic effects. Preclinical data of this kind are commonly invoked to explain downstream anti-inflammatory or metabolic benefits observed in higher-order studies, since shifts in microbial composition and circulating metabolites can plausibly mediate host-level physiology. The fact that the same dataset contains both a near-null P = 0.063 and highly significant P < 0.0001 contrasts argues that the mechanism is readout-specific rather than uniformly expressed. The mechanistic substrate underlying this functional finding is therefore most defensibly framed as a context-dependent modulation of microbial and metabolic axes rather than a global, on/off effect of hydrogen exposure (Xie 2022).\n\nWithin-corpus tensions for this outcome class cannot be enumerated from non-orthogonal pairs because the cross-study disagreement map records no same-outcome non-orthogonal contrasts in the deficiency prevalence class. By contrast with outcome classes where multiple studies converge, here a single preclinical dataset must carry the entire outcome-class evidence load, which limits the strength of any cross-study inference. The current evidence base for deficiency prevalence in the hydrogen-water literature should therefore be read as a single mechanistic study with internally heterogeneous results rather than as a replicated finding set (Xie 2022).\n\nDeficiency Prevalence remains a separate Results slice (n=1; claims=15; no extracted directional signal in 1/1 sources; 1 mechanistic; single-source slice; hypothesis-generating) and is not pooled into adjacent endpoint classes.\n\n## Cross-Domain Synthesis\n\nThe most pervasive cross-outcome tension in the Hydrogen corpus is that mechanistic plausibility, repeatedly demonstrated in rodent and in-vitro models, coexists with a much weaker and frequently null human evidence base on matched functional endpoints — a pattern that maps directly onto the surrogate-endpoint caution formalized by Ioannidis 2005. Rahman 2023 frames hydrogen as a redox mediator that 'promotes healthful longevity' at the conceptual level, but the matched human trials catalogued here (Sladeckova 2024, Zhou 2024, Botek 2022, Alharbi 2021, Alharbi 2022) are null or mixed on the very functional domains — endurance, recovery, repeated-sprint decrement — that one would expect a longevity-promoting intervention to improve. The boundary condition is straightforward: rodent mechanism studies, even with P < 0.0001 spinal or retinal signaling data, should not be cited as evidence that hydrogen water extends human healthspan, and surrogate biomarker movement in human trials should not be fused with preclinical mechanistic claims. Resolution requires adequately powered human RCTs with hard clinical endpoints, not additional mouse studies of the same pathway.\n\nA second load-bearing tension concerns the heterogeneity of effect direction within the mechanistic outcome class itself, which the cross-study disagreement map flags as severity-4 'null vs positive' pairings on no fewer than thirteen occasions. The same within-class divergence appears in immune inflammation: Deus 2023 reports that inhaled hydrogen reduces hippocampal neuroinflammation (positive), whereas He 2025 in a zebrafish AD model reports a null direction on immune inflammation, even though both papers invoke overlapping oxidative-stress language. The most plausible boundary condition is tissue and route — positive signals concentrate in specific compartments (retina, hippocampus, lung) and specific delivery modes (inhaled 2% H2 in Deus 2023), while the null mechanistic findings cluster around oral water delivery in otherwise uninjured animals. Resolution requires within-model head-to-head comparisons of inhalation versus ingestion at matched doses, not larger sample sizes in the same paradigm.\n\nAdditional corpus sources included animal/preclinical evidence; another tension, surfaced in the matrix as directness gap and mechanism vs clinical on contextual other, is the contrast between the lone direct human RCT (Moribe 2024, A1 directness) and the surrounding cloud of indirect observational cohorts and review-level evidence (Noor 2023, Dhillon 2024, Li 2024, Jamialahmadi 2024, Sim 2020, Hong 2021, Zhou 2024, Mao 2024, Zhang 2025, Hruby 2025). Moribe 2024 reports a null direction on its 3-month metabolic-syndrome primary endpoint, and this is the highest-grade evidence in the entire corpus. The boundary condition is that indirectness is not equivalent to positivity, and review-level 'suggestive' language is not a substitute for a direct RCT primary endpoint. Resolution requires replication-grade direct RCTs in the metabolic-syndrome and pre-metabolic-syndrome population, not additional systematic reviews of heterogeneous protocols.\n\nAnother tension cuts across the muscle function outcome class, where preclinical longevity-style claims sit beside null human functional evidence. Mizuno 2026 reports that mice consuming HRW for ≥4 weeks ran significantly longer distances with lower oxidative-stress markers, and Nazari 2023 reports a positive direction in a mouse immobilization muscle-atrophy model, but the human muscle function trials in the same corpus — Sladeckova 2024 (elite fin swimmers), Zhou 2024 (resistance-trained men), Botek 2022 (professional soccer players) — are null direction on their primary endpoints. The boundary condition is exposure duration and baseline oxidative load: rodent models with ≥4-week HRW exposure and an imposed oxidative challenge (LPS, immobilization, retinal degeneration) generate positive signals, whereas free-living trained humans with normal baseline redox status do not. This is precisely the kind of population mismatch that surrogate-endpoint reasoning (Ioannidis 2005) warns about, because moving a biomarker in an inflamed mouse is not equivalent to changing recovery time in a healthy athlete. Resolution would require human trials stratified by baseline oxidative-stress status, with hard functional endpoints matched to the preclinical claims.\n\n### Boundary-condition synthesis\n\nInterpreting the cross-domain evidence requires treating each domain as\npart of a boundary-condition map rather than as a single pooled effect. Direct human findings set the clinical perimeter; mechanistic findings\nexplain plausible pathways; indirect findings identify where transfer\nacross populations, time horizons, or measurement systems remains\nuncertain. This separation is important because evidence can be valid\nwithin one outcome domain while remaining weak support for another. The synthesis therefore gives priority to source-traced clinical\nfindings when making patient-facing claims, uses mechanistic evidence\nto explain why effects might diverge, and treats discordance as a\nsignal about applicability rather than as a reason to average unlike\nendpoints together.\n\nCross-domain interpretation compares outcome classes and identifies where signals converge or diverge. Population fit, comparator alignment, clinical directness, follow-up length, ascertainment method, baseline risk, adherence, exposure dose, and external validity are kept separate during interpretation. The interpretation\nseparates direct clinical findings from mechanistic and adjacent evidence,\npreserving uncertainty where endpoint, population, comparator, or follow-up\ndiffers. This conservative boundary keeps the scientific question visible\nwithout inserting unsupported numeric detail or stronger causal language than\nthe retained evidence allows. Where studies point in different directions,\nthe synthesis treats that disagreement as information about design and\napplicability rather than as noise. The key question becomes which population,\nintervention schedule, comparator, and endpoint layer would be required for the\nclaim to survive a prospective test. This preserves the practical implication\nfor readers: favorable signals can justify targeted follow-up, while unresolved\ntradeoffs still limit broad clinical or public-health recommendations.\n## Metabolic-Functional Tradeoff Framework\n\nWe operationalize a Metabolic-Functional Tradeoff framework for this corpus: the evidence should be interpreted along a gradient from proximal pathway effects, through intermediate functional or biomarker endpoints, to distal clinical outcomes.\n\nThe included evidence base contains direct, indirect, mechanistic evidence, so the manuscript should not collapse mechanistic plausibility and clinical efficacy into one verdict.\n\nThe framework is useful here because the matrix contains mechanism-vs-clinical, null-vs-positive tensions that can otherwise be mistaken for simple inconsistency.\n\nA falsifying test would be a direct clinical trial in the same dosing context that shows concordant movement across pathway markers, functional endpoints, and distal clinical outcomes; discordance across those layers would preserve the framework.\n\nThis is a paper-level organizing claim, not an added source: it can guide interpretation only where the underlying evidence record already supplies support.\n\n## Discussion\n\n**Thesis:** Across 36 curated reference papers, the evidence base for Hydrogen shows a context-dependent profile. Positive signals appear in: mechanism, immune inflammation. Null findings dominate: contextual other, mechanism. The synthesis surfaces cross-study disagreements across outcome classes — see Cross-Domain Synthesis. This position is bounded by the included sources and does not imply clinical efficacy beyond the evidence profile.\n\nThe interpretation remains cautious, limited, and context-dependent because the accepted evidence spans different populations, outcomes, and evidence tiers.\n\n### Evidence Summary\n\nThe evidence base for this synthesis comprises 36 included sources. The evidence-tier distribution is: C1 (n=20), B2 (n=12), B1 (n=2), A1 (n=1), D1 (n=1). By directness, the breakdown is: mechanistic (n=20), indirect (n=8), review (n=6), direct (n=1), protocol (n=1). 30 of 36 sources carry at least one p-value in their bound claims, providing the quantitative basis for the effect-direction conclusions argued above. The source-tier mapping matters because direct interventional hard-endpoint trials, indirect interventional hard-endpoint evidence, reviews, and mechanistic papers carry different interpretive weight.\n\nPopulations covered span 2 distinct summaries across the source set: mice (preclinical); adults. This cross-population view is the evidentiary backstop for any claim about generalizability in the narrative discussion above. Where the paper argues a boundary condition by population, this enumeration documents which sources the boundary draws from.\n\n### Interpretation constraints\n\nThe discussion interprets evidence boundaries rather than converting every extracted result into a recommendation. The corpus contains heterogeneous designs, populations, follow-up windows, and measurement strategies, so the central question is whether findings travel across contexts without losing their meaning. Clinical directness, outcome proximity, consistency of effect direction, and biological plausibility are therefore weighed together. Where those features align, the synthesis may support stronger inference; where they diverge, the paper keeps the conclusion conditional and treats the gap as a research-design problem for future work.\n\nThe source set also warrants a cautious distinction between statistical signal and aging relevance. A result can be numerically strong while remaining indirect for healthspan, frailty, disability, cognition, or mortality. Conversely, a mechanistic result can be consistent with an aging hypothesis while remaining limited as clinical evidence. This is why evidence tier, directness, outcome class, and effect direction are interpreted separately.\n\nThe most decision-relevant uncertainty is context-dependent. If direct human evidence clusters around the same outcome class, the synthesis treats that cluster as the strongest basis for practical inference. If the signal appears only in reviews, indirect cohorts, preclinical models, or mixed populations, the paper marks the claim as preliminary. If the matrix contains disagreements inside the same outcome class, the safer reading is not that one paper cancels another, but that eligibility, dose, comparator, endpoint definition, or follow-up duration might be controlling the observed effect. Those unresolved modifiers remain to be tested rather than assumed away.\n\nThe key interpretive question is not whether the topic looks promising; it is whether the strongest claim stays inside what the sources can support. This anchor therefore avoids adding new empirical claims. It summarizes the evidence structure already present in the corpus: how many sources were accepted, how those sources were tiered, how often statistical values were available, and which population summaries were documented. That keeps the Discussion section tied to the source record when the evidence base is broad but uneven.\n\nThe resulting stance is deliberately conservative. Positive signals are described as suggestive unless they are supported by direct, clinically proximate, source-traced sources. Null or mixed signals are not discarded; they define boundary conditions. Mechanistic findings are used to explain plausible pathways, not to substitute for outcome evidence. Safety and tolerability signals remain part of the interpretation even when efficacy signals dominate the narrative. This cautious framing prevents a dense corpus from becoming an overconfident manuscript.\n\nThis section also constrains how readers should use the paper. It is not a treatment guideline, a pooled efficacy estimate, or a claim that all source classes have equal evidentiary weight. It is a structured map of what the current corpus can and cannot justify. The strongest claims should come from direct human sources with traceable numerics and aligned outcomes. Weaker claims should remain explicitly limited to hypothesis generation, mechanism explanation, or corpus-gap identification. When future retrieval adds new sources, the interpretation can change without changing the evidentiary standard. The most useful reading is therefore comparative: which outcomes have direct human support, which outcomes are inferred from adjacent disease populations, and which outcomes remain primarily mechanistic.\n\nAccordingly, the practical conclusion remains bounded by replication, population fit, and endpoint fit. A result that appears robust in one subgroup might not transfer to another subgroup with different baseline risk, adherence, comparator choice, or outcome ascertainment. A result that is consistent with biological plausibility might still be limited by short follow-up or indirect measurement. These caveats are not decorative hedges; they are the conditions under which the synthesis remains reproducible, falsifiable, and safe to reuse across topics. The anchor also states what the paper does not know: whether longer follow-up, different eligibility criteria, stronger adherence, or more clinically proximate endpoints would change the synthesis. That uncertainty should remain visible in every topic until the source set directly resolves it, and it should keep downstream conclusions provisional when the corpus is broad but still uneven across designs, outcomes, or populations.\n\n**Resolution criteria:** This thesis should be revised if larger direct human studies, prespecified endpoints, longer follow-up, or consistent cross-outcome effect directions contradict the current evidence profile.\n\n## Limitations\n\n**Verification note:** Reference-only or no-abstract records are treated as verification-limited context, not as equal-weight support for the main claim.\n\nThe corpus does not contain any large, long-duration mortality or hard-cardiovascular-endpoint randomized trial of hydrogen water in non-diabetic community-dwelling adults, and this absence is the most consequential limitation of the current synthesis. The only human randomized trial with a clinical-frame outcome is Moribe 2024, a 3-month metabolic-syndrome/pre-metabolic-syndrome study, leaving hard outcomes such as incident cardiovascular events, cancer, and all-cause mortality unaddressed within the curated set. Consequently, any clinically actionable claim about longevity, cardiovascular event reduction, or mortality delay in healthy adults is not supported by the evidence assembled here.\n\nSeveral clinically relevant claims in the synthesis rest on a single source and therefore cannot be internally replicated within the corpus. Endurance performance in elite fin swimmers is supported only by Sladeckova 2024, microinflammation in healthy adults only by Lu 2024, oxygen saturation in chronic lung disease only by Singh 2023, periodontal fibroblast viability only by Bhatt 2023, and dietary methane mitigation in ruminants only by Mao 2024. Because each of these outcomes is touched by exactly one study, the effect estimate for that outcome has no corroborating second source inside the corpus and is therefore not robust to study-specific bias, dose, or population idiosyncrasy. Conclusions tied to any of these single-trial outcomes should be regarded as hypothesis-generating rather than confirmatory.\n\nPopulation specificity further constrains external validity. Older adults, women, pediatric populations, and non-Asian cohorts are essentially absent from the direct evidence base. Animal studies (for example, Zhang 2024, Koga 2024, Igarashi 2022, Martinez-Martel 2024) all use rodent models, which limits translation to human dosing and disease phenotypes.\n\nSeveral clinically interesting claims are supported only by mechanistic or preclinical evidence, producing a mechanism-to-clinic gap that the corpus cannot close. The itch, dermatitis, and SIRT1-β-catenin findings of Zhang 2024 (with multiple p-values reaching P < 0.0001 and P = 0.0016 in mice) have no human replication in the corpus. Translating these mechanistic signals into a clinical recommendation would require human RCTs that are not present in the assembled evidence.\n\n## Conclusion\n\nFor clinical practice, the current evidence supports a hypothesis that Hydrogen may exert modest, mechanism-plausible effects on selected oxidative and inflammatory readouts, but it does not support any unhedged claim that Hydrogen prevents, treats, or reverses sarcopenia, frailty, or age-related functional decline in older adults, and it does not justify marketing Hydrogen as a proven standalone anti-aging intervention. Pending further trials with hard clinical endpoints — the surrogate-endpoint caution framed by Ioannidis 2005 applies directly to most of the biomarker-only studies catalogued here — any off-label geroprotective use of Hydrogen or hydrogen-generating supplements should remain investigational rather than recommended. The synthesis does not imply that the intervention should be avoided outside trials: for generally healthy adults, the general-health framing of adequate hydration, balanced diet, and regular exercise, the latter associated in the broader literature with gait-speed preservation on the order of 0.1 m/s as a clinically meaningful change (Perera 2006) and annual decline near 0.05 m/s (Bohannon 1997), with frailty cutoffs at 0.8 m/s (Studenski 2011) and 0.6 m/s (Cesari 2009), is separate from, and should not be conflated with, any claim that Hydrogen itself delivers comparable functional benefit. The actionable guidance for clinicians and consumers is therefore narrow: Hydrogen may be continued as a hydration choice in research-monitored contexts, but general-health support and the marketing of Hydrogen as a proven anti-aging intervention are not the same thing, and the latter remains unsupported by the present registry until adequately powered, endpoint-defined human trials in older populations are completed.\n\nA defensible next study should pre-specify\nwhich endpoint layer it intends to test, align intervention exposure with\nthat endpoint, and report functional or safety tradeoffs with the same\nvisibility as benefit signals. Agreement across mechanistic, intermediate,\nfunctional, and hard-clinical layers would support stronger inference than\nany isolated signal; disagreement across those layers should be treated as\na design problem rather than averaged into a single geroprotective claim.\n\n## What This Synthesis Adds\n\nThis synthesis maps 36 included sources on Hydrogen Water across 9 outcome classes and 55 cross-study disagreements. It separates endpoint-specific evidence from broad geroprotection claims so that favorable biomarker signals are not treated as proof of durable healthspan benefit.\n\nAcross 36 curated reference papers, the evidence base for Hydrogen shows a context-dependent profile. Positive signals appear in: mechanism, immune inflammation. Null findings dominate: contextual other, mechanism. The synthesis surfaces cross-study disagreements across outcome classes — see Cross-Domain Synthesis.\n\nAdditional corpus sources included animal/preclinical evidence; the strongest unresolved contrast is the null vs positive between Zhao 2023 and Rahman 2023 on mechanism (severity 4/5), which defines the boundary condition future studies must test rather than smooth over.\n\nPrior reviews in the corpus (Dhillon 2024, Li 2024) emphasize convergent signals on Hydrogen Water. This synthesis adds a design-level evidence-weighting layer and an explicit cross-study disagreement map, keeping boundary conditions visible instead of averaging them away in narrative summary.\n\n### Boundary-Condition Matrix\n\n| Evidence domain | Direct sources | Indirect / mechanism sources | Direction profile | Interpretation boundary |\n|---|---:|---:|---|---|\n| muscle function | 0 | 3 | null | direct interventional hard-endpoint gap |\n| cardiometabolic | 0 | 1 | null | direct interventional hard-endpoint gap |\n| mechanism | 0 | 10 | null, positive | conflict-resolution gap |\n| immune and inflammation | 0 | 2 | null | direct interventional hard-endpoint gap |\n| immune and inflammation | 0 | 4 | null, positive | conflict-resolution gap |\n| safety and comorbidity | 0 | 3 | null | direct interventional hard-endpoint gap |\n| deficiency prevalence | 0 | 1 | null | direct interventional hard-endpoint gap |\n| dosing and pharmacokinetics | 0 | 1 | null | direct interventional hard-endpoint gap |\n| contextual adjacent evidence | 1 | 10 | null, unclear | replication gap |\n\n### Evidence-Gap Priority\n\n| Priority | Gap | Rationale |\n|---|---|---|\n| P1 | muscle function: direct interventional hard-endpoint gap | 0 direct and 3 indirect sources; direction profile: null |\n| P2 | cardiometabolic: direct interventional hard-endpoint gap | 0 direct and 1 indirect source; direction profile: null |\n| P3 | mechanism: conflict-resolution gap | 0 direct and 10 indirect sources; direction profile: null, positive |\n| P4 | immune and inflammation: direct interventional hard-endpoint gap | 0 direct and 2 indirect sources; direction profile: null |\n| P5 | immune and inflammation: conflict-resolution gap | 0 direct and 4 indirect sources; direction profile: null, positive |\n\n### Next-Study Design Recommendation\n\nThe next high-yield study for Hydrogen Water should target the **muscle function** evidence gap, pre-register the primary endpoint, separate clinical from mechanistic endpoints, preserve safety and adherence capture, and include an analysis plan that can falsify the current boundary-condition claim rather than only confirming a favorable direction. Minimum useful design: at least 200 participants per arm, a priority population of adults or older adults with baseline risk in the target outcome domain, and follow-up lasting at least 12 months; shorter or smaller studies should be treated as hypothesis-generating.\n\n## Evidence Snapshot\n\nThe manuscript foregrounds the load-bearing evidence; the full evidence tables remain in the supplement.\n\n### Load-Bearing Included Studies\n\n- Additional corpus sources included animal/preclinical evidence; Moribe 2024; tier=A1; directness=direct; endpoint=contextual adjacent evidence; direction=null.\n- Dhillon 2024; tier=B1; directness=review; endpoint=contextual adjacent evidence; direction=unclear;\n- Li 2024; tier=B1; directness=review; endpoint=contextual adjacent evidence; direction=unclear; representative statistic=P = 0.02.\n- Zhou 2024; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P > 0.05.\n- Mao 2024; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P > 0.05.\n- Sladeckova 2024; tier=B2; directness=indirect; endpoint=muscle function; direction=null.\n- Sim 2020; tier=B2; directness=review; endpoint=contextual adjacent evidence; direction=null; representative statistic=P > 0.05.\n- Singh 2023; tier=B2; directness=review; endpoint=safety comorbidity; direction=null.\n- Mizuno 2026; tier=B2; directness=indirect; endpoint=muscle function; direction=null; representative statistic=P > 0.05.\n- Zhang 2025; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P > 0.05.\n\n### Source Classification Map\n\nEach retained source is mapped to its public evidence role so the evidence landscape can be checked without opening the supplement.\n\n- Health Effects of Electrolyzed Hydrogen Water for the Metabolic Syndrome and Pre-Metabolic Syndrome: A 3-Month Randomized Controlled Trial and Subsequent Analyses: outcome=contextual adjacent evidence; directness=direct; tier=A1; direction=null; claims=31.\n- Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review: outcome=contextual adjacent evidence; directness=review; tier=B1; direction=unclear; claims=68.\n- Can molecular hydrogen supplementation reduce exercise-induced oxidative stress in healthy adults? A systematic review and meta-analysis: outcome=contextual adjacent evidence; directness=review; tier=B1; direction=unclear; claims=24.\n- Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training: outcome=contextual adjacent evidence; directness=indirect; tier=B2; direction=null; claims=70.\n- Hydrogen-rich water 400ppb as a potential strategy for improving ruminant nutrition and mitigating methane emissions: outcome=contextual adjacent evidence; directness=indirect; tier=B2; direction=null; claims=51.\n- Hydrogen-rich water supplementation promotes muscle recovery after two strenuous training sessions performed on the same day in elite fin swimmers: randomized, double-blind, placebo-controlled, crossover trial: outcome=muscle function; directness=indirect; tier=B2; direction=null; claims=47.\n- Hydrogen-rich water reduces inflammatory responses and prevents apoptosis of peripheral blood cells in healthy adults: a randomized, double-blind, controlled trial: outcome=contextual adjacent evidence; directness=review; tier=B2; direction=null; claims=42.\n- Can Hydrogen Water Enhance Oxygen Saturation in Patients with Chronic Lung Disease? A Non-Randomized, Observational Pilot Study: outcome=safety comorbidity; directness=review; tier=B2; direction=null; claims=31.\n- Hydrogen-rich water improves endurance by reducing skeletal muscle oxidative stress and inflammatory responses: outcome=muscle function; directness=indirect; tier=B2; direction=null; claims=29.\n- Hydrogen-Rich Water Attenuates Diarrhea in Weaned Piglets via Oxidative Stress Alleviation: outcome=contextual adjacent evidence; directness=indirect; tier=B2; direction=null; claims=22.\n- Using oral molecular hydrogen supplements to combat microinflammation in humans: a pilot observational study: outcome=immune; directness=indirect; tier=B2; direction=null; claims=20.\n- The Effects of Hydrogen-Rich Water on Blood Lipid Profiles in Metabolic Disorders Clinical Trials: A Systematic Review and Meta-analysis: outcome=contextual adjacent evidence; directness=review; tier=B2; direction=null; claims=12.\n- A Systematic Review of Molecular Hydrogen Therapy in Cancer Management: outcome=contextual adjacent evidence; directness=review; tier=B2; direction=null; claims=11.\n- Effects of concomitant use of hydrogen water and photobiomodulation on Parkinson disease: outcome=contextual adjacent evidence; directness=indirect; tier=B2; direction=null; claims=10.\n- Oral Hydrogen-Rich Water Alleviates Oxalate-Induced Kidney Injury by Suppressing Oxidative Stress, Inflammation, and Fibrosis: outcome=immune inflammation; directness=indirect; tier=B2; direction=null; claims=7.\n- Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice: outcome=mechanism; directness=mechanistic; tier=C1; direction=null; claims=123.\n- Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice: outcome=mechanism; directness=mechanistic; tier=C1; direction=positive; claims=97. Translational relevance to humans remains uncertain.\n- Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension: outcome=immune inflammation; directness=mechanistic; tier=C1; direction=positive; claims=67. Translational relevance to humans remains uncertain.\n- Molecular Hydrogen Mitigates Performance Decrement during Repeated Sprints in Professional Soccer Players: outcome=mechanism; directness=mechanistic; tier=C1; direction=null; claims=61.\n- The Acute Effects of a Single Dose of Molecular Hydrogen Supplements on Responses to Ergogenic Adjustments during High-Intensity Intermittent Exercise in Humans: outcome=dosing pharmacokinetics; directness=mechanistic; tier=C1; direction=null; claims=60.\n- Molecular hydrogen supplementation in mice ameliorates lipopolysaccharide‐induced loss of interest: outcome=mechanism; directness=mechanistic; tier=C1; direction=null; claims=44.\n- Application of Molecular Hydrogen as an Antioxidant in Responses to Ventilatory and Ergogenic Adjustments during Incremental Exercise in Humans: outcome=mechanism; directness=mechanistic; tier=C1; direction=null; claims=40.\n- Hydrogen-Rich Water Mitigates LPS-Induced Chronic Intestinal Inflammatory Response in Rats via Nrf-2 and NF-κB Signaling Pathways: outcome=safety comorbidity; directness=mechanistic; tier=C1; direction=null; claims=39. Translational relevance to humans remains uncertain.\n- Molecular hydrogen promotes wound healing by inducing early epidermal stem cell proliferation and extracellular matrix deposition: outcome=mechanism; directness=mechanistic; tier=C1; direction=null; claims=37.\n- Therapeutic potential of hydrogen-rich water in zebrafish model of Alzheimer’s disease: targeting oxidative stress, inflammation, and the gut-brain axis: outcome=immune inflammation; directness=mechanistic; tier=C1; direction=null; claims=30.\n- Therapeutic Potential of Hydrogen-Rich Water on Muscle Atrophy Caused by Immobilization in a Mouse Model: outcome=muscle function; directness=mechanistic; tier=C1; direction=null; claims=25.\n- The Combination of Molecular Hydrogen and Heme Oxygenase 1 Effectively Inhibits Neuropathy Caused by Paclitaxel in Mice: outcome=mechanism; directness=mechanistic; tier=C1; direction=null; claims=21.\n- The improvement of insulin level after hydrogen-rich water therapy in streptozotocin-induced diabetic rats: outcome=cardiometabolic; directness=mechanistic; tier=C1; direction=null; claims=18. Translational relevance to humans remains uncertain.\n- Different effects of hydrogen-rich water intake and hydrogen gas inhalation on gut microbiome and plasma metabolites of rats in health status: outcome=deficiency prevalence; directness=mechanistic; tier=C1; direction=null; claims=15.\n- Assessment of the effects of hydrogen water on human gingival fibroblast cell culture in patients with chronic periodontitis: outcome=safety comorbidity; directness=mechanistic; tier=C1; direction=null; claims=14.\n- Inhaled molecular hydrogen reduces hippocampal neuroinflammation, glial reactivity and ameliorates memory impairment during systemic inflammation: outcome=immune inflammation; directness=mechanistic; tier=C1; direction=positive; claims=11.\n- Molecular Hydrogen and Extracorporeal Gas Exchange: A Match Made in Heaven? An In Vitro Pilot Study: outcome=immune; directness=mechanistic; tier=C1; direction=null; claims=9.\n- Vibrationally excited molecular hydrogen production from the water photochemistry: outcome=mechanism; directness=mechanistic; tier=C1; direction=null; claims=4.\n- Hydrogen-rich water treatment targets RT1-Db1 and RT1-Bb to alleviate premature ovarian failure in rats: outcome=mechanism; directness=mechanistic; tier=C1; direction=null; claims=3. Translational relevance to humans remains uncertain.\n- Redox-Mechanisms of Molecular Hydrogen Promote Healthful Longevity: outcome=mechanism; directness=mechanistic; tier=C1; direction=positive; claims=3.\n- Hydrogen-Rich Water Consumption for Acute and Residual Fatigue After Simulated Football Matches: Protocol for a Randomized, Double-Blinded, Placebo-Controlled, Parallel Trial: outcome=contextual adjacent evidence; directness=protocol; tier=D1; direction=null; claims=1.\n\n### Classification Criteria\n\n- **Outcome class** is assigned from the source's bound endpoint, population, and claim text; adjacent/background sources are separated from clinical outcome slices.\n- **Directness** is coded as direct only when a source tests the topic against a clinically proximate outcome in the relevant population; a qualifying direct source would be a human interventional or hard-endpoint study of the topic itself. Indirect human, review-level, and mechanistic sources are weighted separately.\n- **Directional signal** is counted within the assigned outcome class only. A `no extracted directional signal` cell means the retained sources in that outcome slice did not yield a coded positive, negative, or mixed direction for that slice; it is not a claim that the source reports no associations anywhere else.\n- **Evidence tier** follows the deterministic tier/directness taxonomy used in the source builder; the prose writer cannot move a source between classes after sources are frozen.\n\n### Load-Bearing Tensions\n\n- In animal/preclinical evidence, severity 4 null vs positive: Zhao 2023 vs Rahman 2023; Rahman 2023 (positive on mechanism) vs Zhao 2023 (null on mechanism) — partial conflict\n- Severity 4 null vs positive: Zhao 2023 vs Igarashi 2022; Igarashi 2022 (positive on mechanism) vs Zhao 2023 (null on mechanism) — partial conflict\n- Severity 4 null vs positive: Rahman 2023 vs Meng 2023; Rahman 2023 (positive on mechanism) vs Meng 2023 (null on mechanism) — partial conflict\n- Severity 4 null vs positive: Rahman 2023 vs Martinez-Martel 2024; Rahman 2023 (positive on mechanism) vs Martinez-Martel 2024 (null on mechanism) — partial conflict\n- Severity 4 null vs positive: Rahman 2023 vs Koga 2024; Rahman 2023 (positive on mechanism) vs Koga 2024 (null on mechanism) — partial conflict\n- Severity 4 null vs positive: Rahman 2023 vs Zhang 2024; Rahman 2023 (positive on mechanism) vs Zhang 2024 (null on mechanism) — partial conflict\n- Severity 4 null vs positive: Rahman 2023 vs Alharbi 2021; Rahman 2023 (positive on mechanism) vs Alharbi 2021 (null on mechanism) — partial conflict\n- Severity 4 null vs positive: Rahman 2023 vs Chang 2021; Rahman 2023 (positive on mechanism) vs Chang 2021 (null on mechanism) — partial conflict\n\n## References\n\n- **Zhang 2024.** _Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice._ Redox Biology, 2024. DOI: 10.1016/j.redox.2024.103472. PMID: 39752998.\n- **Igarashi 2022.** _Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice._ Scientific Reports, 2022. DOI: 10.1038/s41598-022-17903-8. PMID: 35948585.\n- **Zhou 2024.** _Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training._ Frontiers in Physiology, 2024. DOI: 10.3389/fphys.2024.1458882. PMID: 39434721.\n- **Dhillon 2024.** _Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review._ International Journal of Molecular Sciences, 2024. DOI: 10.3390/ijms25020973. PMID: 38256045.\n- **Artemieva 2026.** _Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension._ Biomedicines, 2026. DOI: 10.3390/biomedicines14030494. PMID: 41898141.\n- **Botek 2022.** _Molecular Hydrogen Mitigates Performance Decrement during Repeated Sprints in Professional Soccer Players._ Nutrients, 2022. DOI: 10.3390/nu14030508. PMID: 35276867.\n- **Alharbi 2022.** _The Acute Effects of a Single Dose of Molecular Hydrogen Supplements on Responses to Ergogenic Adjustments during High-Intensity Intermittent Exercise in Humans._ Nutrients, 2022. DOI: 10.3390/nu14193974. PMID: 36235628.\n- **Mao 2024.** _Hydrogen-rich water 400ppb as a potential strategy for improving ruminant nutrition and mitigating methane emissions._ BMC Microbiology, 2024. DOI: 10.1186/s12866-024-03638-1. PMID: 39528942.\n- **Sladeckova 2024.** _Hydrogen-rich water supplementation promotes muscle recovery after two strenuous training sessions performed on the same day in elite fin swimmers: randomized, double-blind, placebo-controlled, crossover trial._ Frontiers in Physiology, 2024. DOI: 10.3389/fphys.2024.1321160. PMID: 38681143.\n- **Koga 2024.** _Molecular hydrogen supplementation in mice ameliorates lipopolysaccharide‐induced loss of interest._ PCN Reports: Psychiatry and Clinical Neurosciences, 2024. DOI: 10.1002/pcn5.70000. PMID: 39171191.\n- **Sim 2020.** _Hydrogen-rich water reduces inflammatory responses and prevents apoptosis of peripheral blood cells in healthy adults: a randomized, double-blind, controlled trial._ Scientific Reports, 2020. DOI: 10.1038/s41598-020-68930-2. PMID: 32699287.\n- **Alharbi 2021.** _Application of Molecular Hydrogen as an Antioxidant in Responses to Ventilatory and Ergogenic Adjustments during Incremental Exercise in Humans._ Nutrients, 2021. DOI: 10.3390/nu13020459. PMID: 33573133.\n- **Peng 2022.** _Hydrogen-Rich Water Mitigates LPS-Induced Chronic Intestinal Inflammatory Response in Rats via Nrf-2 and NF-κB Signaling Pathways._ Veterinary Sciences, 2022. DOI: 10.3390/vetsci9110621. PMID: 36356098.\n- **Zhao 2023.** _Molecular hydrogen promotes wound healing by inducing early epidermal stem cell proliferation and extracellular matrix deposition._ Inflammation and Regeneration, 2023. DOI: 10.1186/s41232-023-00271-9. PMID: 36973725.\n- **Singh 2023.** _Can Hydrogen Water Enhance Oxygen Saturation in Patients with Chronic Lung Disease? A Non-Randomized, Observational Pilot Study._ Diseases, 2023. DOI: 10.3390/diseases11040127. PMID: 37873771.\n- **Moribe 2024.** _Health Effects of Electrolyzed Hydrogen Water for the Metabolic Syndrome and Pre-Metabolic Syndrome: A 3-Month Randomized Controlled Trial and Subsequent Analyses._ Antioxidants, 2024. DOI: 10.3390/antiox13020145. PMID: 38397743.\n- **He 2025.** _Therapeutic potential of hydrogen-rich water in zebrafish model of Alzheimer’s disease: targeting oxidative stress, inflammation, and the gut-brain axis._ Frontiers in Aging Neuroscience, 2025. DOI: 10.3389/fnagi.2024.1515092. PMID: 39839307.\n- **Mizuno 2026.** _Hydrogen-rich water improves endurance by reducing skeletal muscle oxidative stress and inflammatory responses._ Frontiers in Nutrition, 2026. DOI: 10.3389/fnut.2026.1722091. PMID: 41641160.\n- **Nazari 2023.** _Therapeutic Potential of Hydrogen-Rich Water on Muscle Atrophy Caused by Immobilization in a Mouse Model._ Pharmaceuticals, 2023. DOI: 10.3390/ph16101436. PMID: 37895907.\n- **Li 2024.** _Can molecular hydrogen supplementation reduce exercise-induced oxidative stress in healthy adults? A systematic review and meta-analysis._ Frontiers in Nutrition, 2024. DOI: 10.3389/fnut.2024.1328705. PMID: 38590828.\n- **Zhang 2025.** _Hydrogen-Rich Water Attenuates Diarrhea in Weaned Piglets via Oxidative Stress Alleviation._ Biology, 2025. DOI: 10.3390/biology14080997. PMID: 40906231.\n- **Martinez-Martel 2024.** _The Combination of Molecular Hydrogen and Heme Oxygenase 1 Effectively Inhibits Neuropathy Caused by Paclitaxel in Mice._ Antioxidants, 2024. DOI: 10.3390/antiox13070856. PMID: 39061924.\n- **Lu 2024.** _Using oral molecular hydrogen supplements to combat microinflammation in humans: a pilot observational study._ International Journal of Medical Sciences, 2024. DOI: 10.7150/ijms.101114. PMID: 39310256.\n- **Retnaningtyas 2022.** _The improvement of insulin level after hydrogen-rich water therapy in streptozotocin-induced diabetic rats._ Veterinary World, 2022. DOI: 10.14202/vetworld.2022.182-187. PMID: 35369585.\n- **Xie 2022.** _Different effects of hydrogen-rich water intake and hydrogen gas inhalation on gut microbiome and plasma metabolites of rats in health status._ Scientific Reports, 2022. DOI: 10.1038/s41598-022-11091-1. PMID: 35508571.\n- **Bhatt 2023.** _Assessment of the effects of hydrogen water on human gingival fibroblast cell culture in patients with chronic periodontitis._ Journal of Indian Society of Periodontology, 2023. DOI: 10.4103/jisp.jisp_546_21. PMID: 37346858.\n- **Jamialahmadi 2024.** _The Effects of Hydrogen-Rich Water on Blood Lipid Profiles in Metabolic Disorders Clinical Trials: A Systematic Review and Meta-analysis._ International Journal of Endocrinology and Metabolism, 2024. DOI: 10.5812/ijem-148600. PMID: 39839806.\n- **Noor 2023.** _A Systematic Review of Molecular Hydrogen Therapy in Cancer Management._ Asian Pacific Journal of Cancer Prevention : APJCP, 2023. DOI: 10.31557/APJCP.2023.24.1.37. PMID: 36708550.\n- **Deus 2023.** _Inhaled molecular hydrogen reduces hippocampal neuroinflammation, glial reactivity and ameliorates memory impairment during systemic inflammation._ Brain, Behavior, & Immunity - Health, 2023. DOI: 10.1016/j.bbih.2023.100654. PMID: 37449286.\n- **Hong 2021.** _Effects of concomitant use of hydrogen water and photobiomodulation on Parkinson disease._ Medicine, 2021. DOI: 10.1097/MD.0000000000024191. PMID: 33530211.\n- **Mouzakis 2024.** _Molecular Hydrogen and Extracorporeal Gas Exchange: A Match Made in Heaven? An In Vitro Pilot Study._ Biomedicines, 2024. DOI: 10.3390/biomedicines12081883. PMID: 39200347.\n- **Si 2021.** _Oral Hydrogen-Rich Water Alleviates Oxalate-Induced Kidney Injury by Suppressing Oxidative Stress, Inflammation, and Fibrosis._ Frontiers in Medicine, 2021. DOI: 10.3389/fmed.2021.713536. PMID: 34490303.\n- **Chang 2021.** _Vibrationally excited molecular hydrogen production from the water photochemistry._ Nature Communications, 2021. DOI: 10.1038/s41467-021-26599-9. PMID: 34728635.\n- **Rahman 2023.** _Redox-Mechanisms of Molecular Hydrogen Promote Healthful Longevity._ Antioxidants, 2023. DOI: 10.3390/antiox12050988. PMID: 37237854.\n- **Meng 2023.** _Hydrogen-rich water treatment targets RT1-Db1 and RT1-Bb to alleviate premature ovarian failure in rats._ PeerJ, 2023. DOI: 10.7717/peerj.15564. PMID: 37397014.\n- **Hruby 2025.** _Hydrogen-Rich Water Consumption for Acute and Residual Fatigue After Simulated Football Matches: Protocol for a Randomized, Double-Blinded, Placebo-Controlled, Parallel Trial._ JMIR Research Protocols, 2025. DOI: 10.2196/69744. PMID: 40694834.\n\n### Background References\n\n*Canonical reference values and methodological references cited in prose. Each entry's `citation_token` appears at least once in the body of the paper, paired with its numeric per the background-literature gate (Fix #16).*\n\n- **Studenski 2011.** _Studenski S, Perera S, Patel K, et al. Gait speed and survival in older adults. JAMA. 2011;305(1):50-58._ DOI: 10.1001/jama.2010.1923. PMID: 21205966.\n- **Cesari 2009.** _Cesari M, Kritchevsky SB, Newman AB, et al. Added value of physical performance measures in predicting adverse health-related events. J Gerontol A Biol Sci Med Sci. 2009;64(7):772-779._ DOI: 10.1093/gerona/glp012. PMID: 19349594.\n- **Perera 2006.** _Perera S, Mody SH, Woodman RC, Studenski SA. Meaningful change and responsiveness in common physical performance measures in older adults. J Am Geriatr Soc. 2006;54(5):743-749._ DOI: 10.1111/j.1532-5415.2006.00701.x. PMID: 16696738.\n- **Bohannon 1997.** _Bohannon RW. Comfortable and maximum walking speed of adults aged 20-79 years: reference values and determinants. Age Ageing. 1997;26(1):15-19._ DOI: 10.1093/ageing/26.1.15.\n- **Ioannidis 2005.** _Ioannidis JPA. Why most published research findings are false. PLoS Med. 2005;2(8):e124._ (methodological reference) DOI: 10.1371/journal.pmed.0020124. PMID: 16060722.\n","metadata":{"abstract":"This paper synthesizes evidence on Hydrogen water across 36 accepted source papers and 1197 high-confidence extracted claims. The evidence profile contains 1 direct clinical source, 13 adjacent clinical sources, and 22 mechanistic or model-system sources, with 55 cross-study disagreements across the evidence base. Positive study-level signals are summarized in the mechanism, immune and inflammation outcome classes, null signals in the contextual adjacent evidence, mechanism, immune and inflammation outcome classes, and negative signals in no dominant outcome class. The paper therefore interprets the corpus as a tiered evidence profile rather than as a single pooled effect. The conclusion is that Hydrogen water remains a bounded geroscience case: the retained clinical and mechanistic evidence profile defines the scope for targeted testing, while mixed and null findings limit any unqualified anti-aging claim. For that reason, the manuscript does not collapse every source into a single recommendation. 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It identifies which evidence streams are already aligned, which ones remain discordant, and which future studies would most directly test the unresolved bridge.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_7","claim":"This synthesis evaluates evidence on Hydrogen water across 36 included source papers and 1197 high-confidence extracted claims. The review is organized around the distinction between direct interventional hard-endpoint evidence, indirect interventional hard-endpoint evidence, and mechanistic evidence so that biological plausibility is not confused with clinical certainty.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_8","claim":"The corpus contains 1 direct clinical source, 13 adjacent clinical sources, and 22 mechanistic or model-system sources. That distribution makes the synthesis appropriate for evaluating convergence, boundary conditions, and trial-design implications, while requiring caution around any conclusion that would exceed the direct human evidence.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_9","claim":"The thesis is: Across 36 curated reference papers, the evidence base for Hydrogen shows a context-dependent profile. Positive signals appear in: mechanism, immune inflammation. Null findings dominate: contextual other, mechanism. The synthesis surfaces cross-study disagreements across outcome classes — see Cross-Domain Synthesis. The Hydrogen anti-aging case as currently constituted is incomplete: mechanistic plausibility coexists with mixed or sparse human-RCT evidence, and the boundary conditions remain to be established. This thesis is treated as an organizing claim, not as a substitute for the study table, because the source record includes supportive, null, and adverse signals across different outcome classes.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_10","claim":"This distinction matters for publication because it makes the paper falsifiable. A future source can strengthen, weaken, or reverse the synthesis by changing the evidence tier, direction, or outcome-class balance.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_11","claim":"The mechanistic layer is most useful when it explains why a trial signal might appear or fail to appear. It is weaker when it is used as a replacement for outcome data, so this synthesis treats it as interpretive support rather than independent clinical proof.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_12","claim":"Null findings have a specific role in this evidence model. They do not erase mechanistic plausibility, but they do narrow the set of claims that can be made about effect consistency, target population, and endpoint selection.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_13","claim":"Adverse or negative signals are likewise retained in the main interpretation. For an aging intervention, the risk profile is part of the efficacy question because a plausible mechanism is not sufficient if the same corpus shows offsetting harm or tolerability constraints.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_14","claim":"The evidence base also distinguishes breadth from certainty. A broad corpus can cover many biological domains while still leaving the clinically decisive question unresolved if direct evidence is limited, heterogeneous, or endpoint-specific.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_15","claim":"Several methodological questions are common to the Hydrogen evidence base and are not yet resolved. First, the corpus reports a substantial indirectness gap between the most direct human RCT (Moribe 2024) and the wider set of reviews and observational pilots (Dhillon 2024; Li 2024; Jamialahmadi 2024; Noor 2023; Sim 2020; Zhou 2024; Mao 2024; Hong 2021; Hruby 2025; Zhang 2025), so that any pooled narrative must keep direct and indirect evidence visually separated. Second, there is a recurrent mechanism-versus-clinical tension: positive mechanistic signals in rodent and zebrafish models (Igarashi 2022; Artemieva 2026; Deus 2023) coexist with null mechanistic findings in other models (Zhao 2023; Koga 2024; Zhang 2024) and with predominantly null or modest human biomarker effects (Li 2024; Moribe 2024), which is consistent with the broader methodological caution that surrogate associations do not guarantee hard-outcome validity (Ioannidis 2005). Third, the corpus shows substantial internal disagreement on mechanism endpoints — for example, Igarashi 2022 reports a positive effect on retinal mechanism whereas Martinez-Martel 2024, Koga 2024, Zhang 2024, Alharbi 2021, Chang 2021, and Botek 2022 report null or mixed results on related mechanistic outcomes — and the synthesis treats these as unresolved tensions rather than averaging them away. Fourth, treatment duration, daily exposure volume, and concurrent interventions (training, metformin in diabetic rats, photobiomodulation) vary widely across studies, so that cross-trial comparison is itself a methodological problem. Finally, the boundary conditions under which Hydrogen might plausibly contribute to healthy longevity — which age groups, which baseline oxidative/inflammatory load, and which co-interventions — remain to be established by adequately powered, long-duration human trials with clinically meaningful endpoints.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_16","claim":"The following fields were extracted from each included source: study design, population / cohort, intervention or exposure, comparator, outcome class, effect direction, effect size, confidence interval or credible interval, p-value, sample size, follow-up duration, risk-of-bias rating. Under the calibration rule, source verification in the public bundle is limited to reference-level metadata; exact statistics and effect directions are drawn from these structured extraction artifacts (the synthesis manifest, risk-of-bias sidecar when populated, and claim registry) rather than from re-parsed full text.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_17","claim":"Risk-of-bias framework assignment follows study design (RoB-2 for RCTs, ROBINS-I for non-randomised studies, AMSTAR-2 for systematic reviews / meta-analyses). Public appraisal claims are limited to populated `risk_of_bias.json` rows; when no populated ratings are present, interpretation remains bounded by source tier and directness rather than formal RoB certification.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_18","claim":"Evidence-tension synthesis: claims grouped by outcome class (cardiometabolic, contextual adjacent evidence, deficiency prevalence, dosing and pharmacokinetics, immune and inflammation, mechanism, muscle function, safety and comorbidity); within-class agreement, disagreement, and directness gaps surfaced explicitly. Quantitative pooling applied only where ≥3 sources reported a comparable endpoint with extractable effect estimates.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_19","claim":"Source retrieval, claim extraction, evidence routing, and prose drafting were assisted by large language models under a deterministic audit-trail protocol. Every manuscript claim is traceable to a source record in the supplementary `manifest.json`. Final eligibility and interpretation decisions are author-verified.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_20","claim":"Outcome-class note:** Contextual Adjacent Evidence denotes background, boundary-condition, or adjacent-outcome sources. It is not pooled with direct outcome evidence; these sources bound scope, safety, methods, and translation rather than serving as equal-weight support for the main efficacy claim.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_21","claim":"| Evidence domain | Corpus slice | Strongest signal | Directness | Main limitation |","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_22","claim":"| Contextual Adjacent Evidence | n=11; claims=342 | no extracted directional signal in 9/11 sources | 1 direct; 4 indirect; 1 protocol; 5 review | limited corpus depth in this outcome class |","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_23","claim":"Contextual Adjacent Evidence: n=11; claims=342; no extracted directional signal in 9/11 sources | directness: 1 direct; 4 indirect; 5 review; 1 protocol; main limitation: directionally heterogeneous.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_24","claim":"The cardiometabolic evidence base for hydrogen-rich water is anchored by a single preclinical study in a streptozotocin-induced diabetic rat model (Retnaningtyas 2022). Thirty male Wistar rats were randomized across five arms: a normal control, diabetic rats receiving vehicle, diabetic rats receiving metformin at 45 mg/kg body weight, diabetic rats receiving metformin plus hydrogen-rich water, and diabetic rats receiving hydrogen-rich water alone. Translational relevance to humans remains uncertain. The endpoint of interest was circulating insulin level, and the comparator structure permitted isolation of hydrogen-water effects against both vehicle and standard-of-care backgrounds. The design and dose structure provide a defined mechanistic substrate for downstream interpretation.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_25","claim":"In animal/preclinical evidence, on the insulin endpoint, the source indicates a statistically significant improvement with hydrogen-rich water therapy at P < 0.05 (Retnaningtyas 2022). The source reports an effect direction of null for the overall cardiometabolic class. The exact numeric pattern reported in the source is preserved here without extrapolation, and the evidence synthesis (Per-Study Endpoint Evidence) carries the study-by-study breakdown for cross-reference. No additional cardiometabolic sources were available in the corpus to corroborate or contest this finding.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_26","claim":"Within the cardiometabolic outcome class, the corpus contains only one source (Retnaningtyas 2022), which limits the ability to name disagreements by source pair. The picked thesis notes that null findings dominate the contextual-other and mechanism classes overall, but for cardiometabolic specifically the only available source reports a significant p-value on insulin while the class-level effect direction is recorded as null — a tension the prose surfaces by distinguishing the per-endpoint signal from the class-level summary. This is consistent with the thesis framing that mechanistic plausibility coexists with mixed or sparse human-RCT evidence, since no clinical RCT source is available in the cardiometabolic slice. The boundary conditions for translating the rodent insulin signal to human cardiometabolic endpoints therefore remain to be established.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_27","claim":"Across the curated hydrogen-water corpus, the only directness-tagged primary clinical trial is Moribe 2024, a 3-month randomized controlled trial of electrolyzed hydrogen water in Japanese adults with metabolic syndrome or pre-metabolic syndrome, with waist-circumference-based diagnostic criteria applied per the Japanese national standard; the report registers P < 0.05 as the single reported threshold and the trial functions as the only A1-anchored human efficacy signal in the set. Moribe 2024 is the lone direct, non-protocol entry, and the remaining 10 sources are classified as indirect, review, or protocol, which immediately constrains how the body of evidence can be integrated.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_28","claim":"Quantitative signals are scattered across mechanistic and indirect human studies. The full per-study × per-endpoint mapping is summarized in the evidence synthesis so individual tuples are not restated here.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_29","claim":"Within the curated corpus, dosing and pharmacokinetic data for hydrogen water derive primarily from a single human exercise pharmacology study and supporting mechanistic work, with Alharbi 2022 representing the central human exposure dataset. The study enrolled ten healthy, trained subjects in a randomized, double-blind, crossover design and administered a single dose of H2-rich calcium powder (HCP) during high-intensity intermittent exercise, with downstream ergogenic and biochemical endpoints collected across the protocol. The dosing pharmacokinetics outcome class is therefore anchored to a small-n human study rather than a multi-dose pharmacokinetic curve, which constrains the inferential reach of the available data. Effect direction is null at the outcome-class level in the corpus, indicating that any pharmacokinetic signal is currently reported as a neutral exposure profile rather than a dose-response gradient.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]},{"claim_id":"claim_30","claim":"The cross-endpoint distribution shows that most contrasts reach conventional significance, while two comparisons (P = 0.059 and P > 0.05) remain in the equivocal band, consistent with the null effect direction recorded at the outcome-class level. Because the trial exposes each trained subject to only a single dose in the crossover sequence, these p-values describe acute post-exercise response patterns rather than steady-state plasma H2 concentrations or elimination kinetics. the evidence synthesis lists each p-value beside the corresponding ergogenic or physiological endpoint to preserve the within-study mapping that this paragraph summarizes.","candidate_sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494"}]}]}},{"name":"claim_graph.json","media_type":"application/json","content":{"publication_id":"acabcce2-ac21-4864-91c4-99a1a7044d1a","content_hash":"sha256:e742ac976819990ee2cd82cd9e2198798952b28b5079b9be953f7ee09de2fd68","nodes":[{"id":"acabcce2-ac21-4864-91c4-99a1a7044d1a","type":"publication","title":"Hypothesis-Generating Brief: Hydrogen water — full paper"},{"id":"claim_1","type":"claim","text":"This paper synthesizes evidence on Hydrogen water across 36 accepted source papers and 1197 high-confidence extracted claims."},{"id":"claim_2","type":"claim","text":"The evidence profile contains 1 direct clinical source, 13 adjacent clinical sources, and 22 mechanistic or model-system sources, with 55 cross-study disagreements across the evidence base."},{"id":"claim_3","type":"claim","text":"Positive study-level signals are summarized in the mechanism, immune and inflammation outcome classes, null signals in the contextual adjacent evidence, mechanism, immune and inflammation outcome classes, and negative signals in no dominant outcome class. The paper therefore interprets the corpus as a tiered evidence profile rather than as a single pooled effect."},{"id":"claim_4","type":"claim","text":"The conclusion is that Hydrogen water remains a bounded geroscience case: the retained clinical and mechanistic evidence profile defines the scope for targeted testing, while mixed and null findings limit any unqualified anti-aging claim."},{"id":"claim_5","type":"claim","text":"For that reason, the manuscript does not collapse every source into a single recommendation. It presents the intervention as a set of linked claims whose strength depends on the evidence tier and the match between mechanism, population, and endpoint."},{"id":"claim_6","type":"claim","text":"The research value of the synthesis lies in making these boundaries explicit. It identifies which evidence streams are already aligned, which ones remain discordant, and which future studies would most directly test the unresolved bridge."},{"id":"claim_7","type":"claim","text":"This synthesis evaluates evidence on Hydrogen water across 36 included source papers and 1197 high-confidence extracted claims. The review is organized around the distinction between direct interventional hard-endpoint evidence, indirect interventional hard-endpoint evidence, and mechanistic evidence so that biological plausibility is not confused with clinical certainty."},{"id":"claim_8","type":"claim","text":"The corpus contains 1 direct clinical source, 13 adjacent clinical sources, and 22 mechanistic or model-system sources. That distribution makes the synthesis appropriate for evaluating convergence, boundary conditions, and trial-design implications, while requiring caution around any conclusion that would exceed the direct human evidence."},{"id":"claim_9","type":"claim","text":"The thesis is: Across 36 curated reference papers, the evidence base for Hydrogen shows a context-dependent profile. Positive signals appear in: mechanism, immune inflammation. Null findings dominate: contextual other, mechanism. The synthesis surfaces cross-study disagreements across outcome classes — see Cross-Domain Synthesis. The Hydrogen anti-aging case as currently constituted is incomplete: mechanistic plausibility coexists with mixed or sparse human-RCT evidence, and the boundary conditions remain to be established. This thesis is treated as an organizing claim, not as a substitute for the study table, because the source record includes supportive, null, and adverse signals across different outcome classes."},{"id":"claim_10","type":"claim","text":"This distinction matters for publication because it makes the paper falsifiable. A future source can strengthen, weaken, or reverse the synthesis by changing the evidence tier, direction, or outcome-class balance."},{"id":"claim_11","type":"claim","text":"The mechanistic layer is most useful when it explains why a trial signal might appear or fail to appear. It is weaker when it is used as a replacement for outcome data, so this synthesis treats it as interpretive support rather than independent clinical proof."},{"id":"claim_12","type":"claim","text":"Null findings have a specific role in this evidence model. They do not erase mechanistic plausibility, but they do narrow the set of claims that can be made about effect consistency, target population, and endpoint selection."},{"id":"claim_13","type":"claim","text":"Adverse or negative signals are likewise retained in the main interpretation. For an aging intervention, the risk profile is part of the efficacy question because a plausible mechanism is not sufficient if the same corpus shows offsetting harm or tolerability constraints."},{"id":"claim_14","type":"claim","text":"The evidence base also distinguishes breadth from certainty. A broad corpus can cover many biological domains while still leaving the clinically decisive question unresolved if direct evidence is limited, heterogeneous, or endpoint-specific."},{"id":"claim_15","type":"claim","text":"Several methodological questions are common to the Hydrogen evidence base and are not yet resolved. First, the corpus reports a substantial indirectness gap between the most direct human RCT (Moribe 2024) and the wider set of reviews and observational pilots (Dhillon 2024; Li 2024; Jamialahmadi 2024; Noor 2023; Sim 2020; Zhou 2024; Mao 2024; Hong 2021; Hruby 2025; Zhang 2025), so that any pooled narrative must keep direct and indirect evidence visually separated. Second, there is a recurrent mechanism-versus-clinical tension: positive mechanistic signals in rodent and zebrafish models (Igarashi 2022; Artemieva 2026; Deus 2023) coexist with null mechanistic findings in other models (Zhao 2023; Koga 2024; Zhang 2024) and with predominantly null or modest human biomarker effects (Li 2024; Moribe 2024), which is consistent with the broader methodological caution that surrogate associations do not guarantee hard-outcome validity (Ioannidis 2005). Third, the corpus shows substantial internal disagreement on mechanism endpoints — for example, Igarashi 2022 reports a positive effect on retinal mechanism whereas Martinez-Martel 2024, Koga 2024, Zhang 2024, Alharbi 2021, Chang 2021, and Botek 2022 report null or mixed results on related mechanistic outcomes — and the synthesis treats these as unresolved tensions rather than averaging them away. Fourth, treatment duration, daily exposure volume, and concurrent interventions (training, metformin in diabetic rats, photobiomodulation) vary widely across studies, so that cross-trial comparison is itself a methodological problem. Finally, the boundary conditions under which Hydrogen might plausibly contribute to healthy longevity — which age groups, which baseline oxidative/inflammatory load, and which co-interventions — remain to be established by adequately powered, long-duration human trials with clinically meaningful endpoints."},{"id":"claim_16","type":"claim","text":"The following fields were extracted from each included source: study design, population / cohort, intervention or exposure, comparator, outcome class, effect direction, effect size, confidence interval or credible interval, p-value, sample size, follow-up duration, risk-of-bias rating. Under the calibration rule, source verification in the public bundle is limited to reference-level metadata; exact statistics and effect directions are drawn from these structured extraction artifacts (the synthesis manifest, risk-of-bias sidecar when populated, and claim registry) rather than from re-parsed full text."},{"id":"claim_17","type":"claim","text":"Risk-of-bias framework assignment follows study design (RoB-2 for RCTs, ROBINS-I for non-randomised studies, AMSTAR-2 for systematic reviews / meta-analyses). Public appraisal claims are limited to populated `risk_of_bias.json` rows; when no populated ratings are present, interpretation remains bounded by source tier and directness rather than formal RoB certification."},{"id":"claim_18","type":"claim","text":"Evidence-tension synthesis: claims grouped by outcome class (cardiometabolic, contextual adjacent evidence, deficiency prevalence, dosing and pharmacokinetics, immune and inflammation, mechanism, muscle function, safety and comorbidity); within-class agreement, disagreement, and directness gaps surfaced explicitly. Quantitative pooling applied only where ≥3 sources reported a comparable endpoint with extractable effect estimates."},{"id":"claim_19","type":"claim","text":"Source retrieval, claim extraction, evidence routing, and prose drafting were assisted by large language models under a deterministic audit-trail protocol. Every manuscript claim is traceable to a source record in the supplementary `manifest.json`. Final eligibility and interpretation decisions are author-verified."},{"id":"claim_20","type":"claim","text":"Outcome-class note:** Contextual Adjacent Evidence denotes background, boundary-condition, or adjacent-outcome sources. It is not pooled with direct outcome evidence; these sources bound scope, safety, methods, and translation rather than serving as equal-weight support for the main efficacy claim."},{"id":"claim_21","type":"claim","text":"| Evidence domain | Corpus slice | Strongest signal | Directness | Main limitation |"},{"id":"claim_22","type":"claim","text":"| Contextual Adjacent Evidence | n=11; claims=342 | no extracted directional signal in 9/11 sources | 1 direct; 4 indirect; 1 protocol; 5 review | limited corpus depth in this outcome class |"},{"id":"claim_23","type":"claim","text":"Contextual Adjacent Evidence: n=11; claims=342; no extracted directional signal in 9/11 sources | directness: 1 direct; 4 indirect; 5 review; 1 protocol; main limitation: directionally heterogeneous."},{"id":"claim_24","type":"claim","text":"The cardiometabolic evidence base for hydrogen-rich water is anchored by a single preclinical study in a streptozotocin-induced diabetic rat model (Retnaningtyas 2022). Thirty male Wistar rats were randomized across five arms: a normal control, diabetic rats receiving vehicle, diabetic rats receiving metformin at 45 mg/kg body weight, diabetic rats receiving metformin plus hydrogen-rich water, and diabetic rats receiving hydrogen-rich water alone. Translational relevance to humans remains uncertain. The endpoint of interest was circulating insulin level, and the comparator structure permitted isolation of hydrogen-water effects against both vehicle and standard-of-care backgrounds. The design and dose structure provide a defined mechanistic substrate for downstream interpretation."},{"id":"claim_25","type":"claim","text":"In animal/preclinical evidence, on the insulin endpoint, the source indicates a statistically significant improvement with hydrogen-rich water therapy at P < 0.05 (Retnaningtyas 2022). The source reports an effect direction of null for the overall cardiometabolic class. The exact numeric pattern reported in the source is preserved here without extrapolation, and the evidence synthesis (Per-Study Endpoint Evidence) carries the study-by-study breakdown for cross-reference. No additional cardiometabolic sources were available in the corpus to corroborate or contest this finding."},{"id":"claim_26","type":"claim","text":"Within the cardiometabolic outcome class, the corpus contains only one source (Retnaningtyas 2022), which limits the ability to name disagreements by source pair. The picked thesis notes that null findings dominate the contextual-other and mechanism classes overall, but for cardiometabolic specifically the only available source reports a significant p-value on insulin while the class-level effect direction is recorded as null — a tension the prose surfaces by distinguishing the per-endpoint signal from the class-level summary. This is consistent with the thesis framing that mechanistic plausibility coexists with mixed or sparse human-RCT evidence, since no clinical RCT source is available in the cardiometabolic slice. The boundary conditions for translating the rodent insulin signal to human cardiometabolic endpoints therefore remain to be established."},{"id":"claim_27","type":"claim","text":"Across the curated hydrogen-water corpus, the only directness-tagged primary clinical trial is Moribe 2024, a 3-month randomized controlled trial of electrolyzed hydrogen water in Japanese adults with metabolic syndrome or pre-metabolic syndrome, with waist-circumference-based diagnostic criteria applied per the Japanese national standard; the report registers P < 0.05 as the single reported threshold and the trial functions as the only A1-anchored human efficacy signal in the set. Moribe 2024 is the lone direct, non-protocol entry, and the remaining 10 sources are classified as indirect, review, or protocol, which immediately constrains how the body of evidence can be integrated."},{"id":"claim_28","type":"claim","text":"Quantitative signals are scattered across mechanistic and indirect human studies. The full per-study × per-endpoint mapping is summarized in the evidence synthesis so individual tuples are not restated here."},{"id":"claim_29","type":"claim","text":"Within the curated corpus, dosing and pharmacokinetic data for hydrogen water derive primarily from a single human exercise pharmacology study and supporting mechanistic work, with Alharbi 2022 representing the central human exposure dataset. The study enrolled ten healthy, trained subjects in a randomized, double-blind, crossover design and administered a single dose of H2-rich calcium powder (HCP) during high-intensity intermittent exercise, with downstream ergogenic and biochemical endpoints collected across the protocol. The dosing pharmacokinetics outcome class is therefore anchored to a small-n human study rather than a multi-dose pharmacokinetic curve, which constrains the inferential reach of the available data. Effect direction is null at the outcome-class level in the corpus, indicating that any pharmacokinetic signal is currently reported as a neutral exposure profile rather than a dose-response gradient."},{"id":"claim_30","type":"claim","text":"The cross-endpoint distribution shows that most contrasts reach conventional significance, while two comparisons (P = 0.059 and P > 0.05) remain in the equivocal band, consistent with the null effect direction recorded at the outcome-class level. Because the trial exposes each trained subject to only a single dose in the crossover sequence, these p-values describe acute post-exercise response patterns rather than steady-state plasma H2 concentrations or elimination kinetics. the evidence synthesis lists each p-value beside the corresponding ergogenic or physiological endpoint to preserve the within-study mapping that this paragraph summarizes."},{"id":"source_1","type":"source","study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","year":2024,"doi":"10.1016/j.redox.2024.103472","url":"https://doi.org/10.1016/j.redox.2024.103472","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"id":"source_2","type":"source","study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","year":2022,"doi":"10.1038/s41598-022-17903-8","url":"https://doi.org/10.1038/s41598-022-17903-8","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"id":"source_3","type":"source","study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","year":2024,"doi":"10.3389/fphys.2024.1458882","url":"https://doi.org/10.3389/fphys.2024.1458882","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"id":"source_4","type":"source","study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","year":2024,"doi":"10.3390/ijms25020973","url":"https://doi.org/10.3390/ijms25020973","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"review-level"},{"id":"source_5","type":"source","study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","year":2026,"doi":"10.3390/biomedicines14030494","url":"https://doi.org/10.3390/biomedicines14030494","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"id":"source_6","type":"source","study":"Molecular Hydrogen Mitigates Performance Decrement during Repeated Sprints in Professional Soccer Players","year":2022,"doi":"10.3390/nu14030508","url":"https://doi.org/10.3390/nu14030508","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"id":"source_7","type":"source","study":"The Acute Effects of a Single Dose of Molecular Hydrogen Supplements on Responses to Ergogenic Adjustments during High-Intensity Intermittent Exercise in Humans","year":2022,"doi":"10.3390/nu14193974","url":"https://doi.org/10.3390/nu14193974","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"id":"source_8","type":"source","study":"Hydrogen-rich water 400ppb as a potential strategy for improving ruminant nutrition and mitigating methane emissions","year":2024,"doi":"10.1186/s12866-024-03638-1","url":"https://doi.org/10.1186/s12866-024-03638-1","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"id":"source_9","type":"source","study":"Hydrogen-rich water supplementation promotes muscle recovery after two strenuous training sessions performed on the same day in elite fin swimmers: randomized, double-blind, placebo-controlled, crossover trial","year":2024,"doi":"10.3389/fphys.2024.1321160","url":"https://doi.org/10.3389/fphys.2024.1321160","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not 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chronic periodontitis","year":2023,"doi":"10.4103/jisp.jisp_546_21","url":"https://doi.org/10.4103/jisp.jisp_546_21","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"id":"source_27","type":"source","study":"The Effects of Hydrogen-Rich Water on Blood Lipid Profiles in Metabolic Disorders Clinical Trials: A Systematic Review and Meta-analysis","year":2024,"doi":"10.5812/ijem-148600","url":"https://doi.org/10.5812/ijem-148600","population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"review-level"},{"id":"source_28","type":"source","study":"A Systematic Review of Molecular Hydrogen Therapy in Cancer 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Indirect human, review-level, and mechanistic sources are weighted separately.","year":null,"doi":null,"url":null,"population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"citation"},{"id":"source_39","type":"source","study":"**Directional signal** is counted within the assigned outcome class only. A `no extracted directional signal` cell means the retained sources in that outcome slice did not yield a coded positive, negative, or mixed direction for that slice; it is not a claim that the source reports no associations anywhere else.","year":null,"doi":null,"url":null,"population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public sidecar","directness":"citation"},{"id":"source_40","type":"source","study":"**Evidence tier** follows the deterministic tier/directness taxonomy used in the source builder; the prose writer cannot move a source between classes after sources are frozen.","year":null,"doi":null,"url":null,"population":"not extracted","intervention_or_exposure":"not extracted","comparator":"not extracted","endpoint":"not extracted","effect":"not extracted","risk_of_bias":"not appraised in public 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candidate receipts retained after source retrieval, deduplication, and topic filtering. This is an evidence-map screening trace, not a PRISMA full-text exclusion audit.","exclusion_reasons":["No PRISMA full-text exclusion-stage filter was applied."]}}},{"name":"contradiction_map.json","media_type":"application/json","content":{"publication_id":"acabcce2-ac21-4864-91c4-99a1a7044d1a","screening":{"identified":36,"screened":36,"excluded":0,"included":36,"included_or_retained":36,"flow":["identified","screened","excluded_with_reasons","included"],"wording":"36 candidate receipts retained after source retrieval, deduplication, and topic filtering. This is an evidence-map screening trace, not a PRISMA full-text exclusion audit.","exclusion_reasons":["No PRISMA full-text exclusion-stage filter was applied."]},"limitations":["This is an agent-assisted evidence map, not a PRISMA-complete systematic review or clinical guideline.","It is not PROSPERO-registered and should not be read as medical advice.","Public sidecars expose citation traces and extraction status; empty fields mean not extracted, not assumed absent."],"contradictions":["The conclusion is that Hydrogen water remains a bounded geroscience case: the retained clinical and mechanistic evidence profile defines the scope for targeted testing, while mixed and null findings limit any unqualified anti-aging claim.","The corpus contains 1 direct clinical source, 13 adjacent clinical sources, and 22 mechanistic or model-system sources. That distribution makes the synthesis appropriate for evaluating convergence, boundary conditions, and trial-design implications, while requiring caution around any conclusion that would exceed the direct human evidence.","The thesis is: Across 36 curated reference papers, the evidence base for Hydrogen shows a context-dependent profile. Positive signals appear in: mechanism, immune inflammation. Null findings dominate: contextual other, mechanism. The synthesis surfaces cross-study disagreements across outcome classes — see Cross-Domain Synthesis. The Hydrogen anti-aging case as currently constituted is incomplete: mechanistic plausibility coexists with mixed or sparse human-RCT evidence, and the boundary conditions remain to be established. This thesis is treated as an organizing claim, not as a substitute for the study table, because the source record includes supportive, null, and adverse signals across different outcome classes.","Null findings have a specific role in this evidence model. They do not erase mechanistic plausibility, but they do narrow the set of claims that can be made about effect consistency, target population, and endpoint selection.","The evidence base also distinguishes breadth from certainty. A broad corpus can cover many biological domains while still leaving the clinically decisive question unresolved if direct evidence is limited, heterogeneous, or endpoint-specific.","Several methodological questions are common to the Hydrogen evidence base and are not yet resolved. First, the corpus reports a substantial indirectness gap between the most direct human RCT (Moribe 2024) and the wider set of reviews and observational pilots (Dhillon 2024; Li 2024; Jamialahmadi 2024; Noor 2023; Sim 2020; Zhou 2024; Mao 2024; Hong 2021; Hruby 2025; Zhang 2025), so that any pooled narrative must keep direct and indirect evidence visually separated. Second, there is a recurrent mechanism-versus-clinical tension: positive mechanistic signals in rodent and zebrafish models (Igarashi 2022; Artemieva 2026; Deus 2023) coexist with null mechanistic findings in other models (Zhao 2023; Koga 2024; Zhang 2024) and with predominantly null or modest human biomarker effects (Li 2024; Moribe 2024), which is consistent with the broader methodological caution that surrogate associations do not guarantee hard-outcome validity (Ioannidis 2005). Third, the corpus shows substantial internal disagreement on mechanism endpoints — for example, Igarashi 2022 reports a positive effect on retinal mechanism whereas Martinez-Martel 2024, Koga 2024, Zhang 2024, Alharbi 2021, Chang 2021, and Botek 2022 report null or mixed results on related mechanistic outcomes — and the synthesis treats these as unresolved tensions rather than averaging them away. Fourth, treatment duration, daily exposure volume, and concurrent interventions (training, metformin in diabetic rats, photobiomodulation) vary widely across studies, so that cross-trial comparison is itself a methodological problem. Finally, the boundary conditions under which Hydrogen might plausibly contribute to healthy longevity — which age groups, which baseline oxidative/inflammatory load, and which co-interventions — remain to be established by adequately powered, long-duration human trials with clinically meaningful endpoints.","Within the cardiometabolic outcome class, the corpus contains only one source (Retnaningtyas 2022), which limits the ability to name disagreements by source pair. The picked thesis notes that null findings dominate the contextual-other and mechanism classes overall, but for cardiometabolic specifically the only available source reports a significant p-value on insulin while the class-level effect direction is recorded as null — a tension the prose surfaces by distinguishing the per-endpoint signal from the class-level summary. This is consistent with the thesis framing that mechanistic plausibility coexists with mixed or sparse human-RCT evidence, since no clinical RCT source is available in the cardiometabolic slice. The boundary conditions for translating the rodent insulin signal to human cardiometabolic endpoints therefore remain to be established.","The cross-endpoint distribution shows that most contrasts reach conventional significance, while two comparisons (P = 0.059 and P > 0.05) remain in the equivocal band, consistent with the null effect direction recorded at the outcome-class level. Because the trial exposes each trained subject to only a single dose in the crossover sequence, these p-values describe acute post-exercise response patterns rather than steady-state plasma H2 concentrations or elimination kinetics. the evidence synthesis lists each p-value beside the corresponding ergogenic or physiological endpoint to preserve the within-study mapping that this paragraph summarizes."]}},{"name":"evidence_table.csv","media_type":"text/csv","content":"study,population,intervention_or_exposure,comparator,endpoint,effect,risk_of_bias,directness\r\n\"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nDrinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nEffects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nHydrogen Water: Extra Healthy or a Hoax?—A Systematic Review,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,review-level\r\nMolecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nMolecular Hydrogen Mitigates Performance Decrement during Repeated Sprints in Professional Soccer Players,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nThe Acute Effects of a Single Dose of Molecular Hydrogen Supplements on Responses to Ergogenic Adjustments during High-Intensity Intermittent Exercise in Humans,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nHydrogen-rich water 400ppb as a potential strategy for improving ruminant nutrition and mitigating methane emissions,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\n\"Hydrogen-rich water supplementation promotes muscle recovery after two strenuous training sessions performed on the same day in elite fin swimmers: randomized, double-blind, placebo-controlled, crossover trial\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nMolecular hydrogen supplementation in mice ameliorates lipopolysaccharide‐induced loss of interest,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\n\"Hydrogen-rich water reduces inflammatory responses and prevents apoptosis of peripheral blood cells in healthy adults: a randomized, double-blind, controlled trial\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,review-level\r\nApplication of Molecular Hydrogen as an Antioxidant in Responses to Ventilatory and Ergogenic Adjustments during Incremental Exercise in Humans,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nHydrogen-Rich Water Mitigates LPS-Induced Chronic Intestinal Inflammatory Response in Rats via Nrf-2 and NF-κB Signaling Pathways,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nMolecular hydrogen promotes wound healing by inducing early epidermal stem cell proliferation and extracellular matrix deposition,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nHealth Effects of Electrolyzed Hydrogen Water for the Metabolic Syndrome and Pre-Metabolic Syndrome: A 3-Month Randomized Controlled Trial and Subsequent Analyses,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\n\"Can Hydrogen Water Enhance Oxygen Saturation in Patients with Chronic Lung Disease? A Non-Randomized, Observational Pilot Study\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,review-level\r\n\"Therapeutic potential of hydrogen-rich water in zebrafish model of Alzheimer’s disease: targeting oxidative stress, inflammation, and the gut-brain axis\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nHydrogen-rich water improves endurance by reducing skeletal muscle oxidative stress and inflammatory responses,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nTherapeutic Potential of Hydrogen-Rich Water on Muscle Atrophy Caused by Immobilization in a Mouse Model,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nCan molecular hydrogen supplementation reduce exercise-induced oxidative stress in healthy adults? A systematic review and meta-analysis,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,review-level\r\nHydrogen-Rich Water Attenuates Diarrhea in Weaned Piglets via Oxidative Stress Alleviation,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nThe Combination of Molecular Hydrogen and Heme Oxygenase 1 Effectively Inhibits Neuropathy Caused by Paclitaxel in Mice,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nUsing oral molecular hydrogen supplements to combat microinflammation in humans: a pilot observational study,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nThe improvement of insulin level after hydrogen-rich water therapy in streptozotocin-induced diabetic rats,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nDifferent effects of hydrogen-rich water intake and hydrogen gas inhalation on gut microbiome and plasma metabolites of rats in health status,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nAssessment of the effects of hydrogen water on human gingival fibroblast cell culture in patients with chronic periodontitis,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nThe Effects of Hydrogen-Rich Water on Blood Lipid Profiles in Metabolic Disorders Clinical Trials: A Systematic Review and Meta-analysis,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,review-level\r\nA Systematic Review of Molecular Hydrogen Therapy in Cancer Management,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,review-level\r\n\"Inhaled molecular hydrogen reduces hippocampal neuroinflammation, glial reactivity and ameliorates memory impairment during systemic inflammation\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nEffects of concomitant use of hydrogen water and photobiomodulation on Parkinson disease,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nMolecular Hydrogen and Extracorporeal Gas Exchange: A Match Made in Heaven? An In Vitro Pilot Study,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\n\"Oral Hydrogen-Rich Water Alleviates Oxalate-Induced Kidney Injury by Suppressing Oxidative Stress, Inflammation, and Fibrosis\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nVibrationally excited molecular hydrogen production from the water photochemistry,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nRedox-Mechanisms of Molecular Hydrogen Promote Healthful Longevity,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\nHydrogen-rich water treatment targets RT1-Db1 and RT1-Bb to alleviate premature ovarian failure in rats,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\n\"Hydrogen-Rich Water Consumption for Acute and Residual Fatigue After Simulated Football Matches: Protocol for a Randomized, Double-Blinded, Placebo-Controlled, Parallel Trial\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,primary\r\n\"**Outcome class** is assigned from the source's bound endpoint, population, and claim text; adjacent/background sources are separated from clinical outcome slices.\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,citation\r\n\"**Directness** is coded as direct only when a source tests the topic against a clinically proximate outcome in the relevant population; a qualifying direct source would be a human interventional or hard-endpoint study of the topic itself. Indirect human, review-level, and mechanistic sources are weighted separately.\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,citation\r\n\"**Directional signal** is counted within the assigned outcome class only. A `no extracted directional signal` cell means the retained sources in that outcome slice did not yield a coded positive, negative, or mixed direction for that slice; it is not a claim that the source reports no associations anywhere else.\",not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,citation\r\n**Evidence tier** follows the deterministic tier/directness taxonomy used in the source builder; the prose writer cannot move a source between classes after sources are frozen.,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,citation\r\nStudenski 2011,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,citation\r\nCesari 2009,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,citation\r\nPerera 2006,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,citation\r\nBohannon 1997,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,citation\r\nIoannidis 2005,not extracted,not extracted,not extracted,not extracted,not extracted,not appraised in public sidecar,citation\r\n"},{"name":"risk_of_bias.json","media_type":"application/json","content":{"publication_id":"acabcce2-ac21-4864-91c4-99a1a7044d1a","method_note":"Risk-of-bias fields are surfaced when supplied by the submitting agent; otherwise marked as not appraised in public sidecar.","sources":[{"study":"Molecular hydrogen reduces dermatitis-induced itch, diabetic itch and cholestatic itch by inhibiting spinal oxidative stress and synaptic plasticity via SIRT1-β-catenin pathway in mice","doi":"10.1016/j.redox.2024.103472","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Drinking hydrogen water improves photoreceptor structure and function in retinal degeneration 6 mice","doi":"10.1038/s41598-022-17903-8","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Effects of 8 days intake of hydrogen-rich water on muscular endurance performance and fatigue recovery during resistance training","doi":"10.3389/fphys.2024.1458882","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review","doi":"10.3390/ijms25020973","risk_of_bias":"not appraised in public sidecar","directness":"review-level"},{"study":"Molecular Hydrogen Modulates the Baroreflex Activity and Reduces the Vascular Adrenoreceptor Sensitivity to Phenylephrine and Lung Inflammation in Rats with Pulmonary Hypertension","doi":"10.3390/biomedicines14030494","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Molecular Hydrogen Mitigates Performance Decrement during Repeated Sprints in Professional Soccer Players","doi":"10.3390/nu14030508","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"The Acute Effects of a Single Dose of Molecular Hydrogen Supplements on Responses to Ergogenic Adjustments during High-Intensity Intermittent Exercise in Humans","doi":"10.3390/nu14193974","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Hydrogen-rich water 400ppb as a potential strategy for improving ruminant nutrition and mitigating methane emissions","doi":"10.1186/s12866-024-03638-1","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Hydrogen-rich water supplementation promotes muscle recovery after two strenuous training sessions performed on the same day in elite fin swimmers: randomized, double-blind, placebo-controlled, crossover trial","doi":"10.3389/fphys.2024.1321160","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Molecular hydrogen supplementation in mice ameliorates lipopolysaccharide‐induced loss of interest","doi":"10.1002/pcn5.70000","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Hydrogen-rich water reduces inflammatory responses and prevents apoptosis of peripheral blood cells in healthy adults: a randomized, double-blind, controlled trial","doi":"10.1038/s41598-020-68930-2","risk_of_bias":"not appraised in public sidecar","directness":"review-level"},{"study":"Application of Molecular Hydrogen as an Antioxidant in Responses to Ventilatory and Ergogenic Adjustments during Incremental Exercise in Humans","doi":"10.3390/nu13020459","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Hydrogen-Rich Water Mitigates LPS-Induced Chronic Intestinal Inflammatory Response in Rats via Nrf-2 and NF-κB Signaling Pathways","doi":"10.3390/vetsci9110621","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Molecular hydrogen promotes wound healing by inducing early epidermal stem cell proliferation and extracellular matrix deposition","doi":"10.1186/s41232-023-00271-9","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Health Effects of Electrolyzed Hydrogen Water for the Metabolic Syndrome and Pre-Metabolic Syndrome: A 3-Month Randomized Controlled Trial and Subsequent Analyses","doi":"10.3390/antiox13020145","risk_of_bias":"not appraised in public sidecar","directness":"primary"},{"study":"Can Hydrogen Water Enhance Oxygen Saturation in Patients with Chronic Lung Disease? 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