Effects of Molecular Hydrogen Assessed by an Animal Model and a Randomized Clinical Study on Mild Cognitive Impairment
Nishimaki K et al. · Curr Alzheimer Res. 2018;15(5):482–492.
Study at a glance
Human
Older adults with mild cognitive impairment
One 500 mL pouch of hydrogen-rich water daily · More than 0.6 mM dissolved H₂ when supplied.
1 year
Overall ADAS-cog did not differ significantly between groups. Favorable findings were reported in the small APOE4-carrier subgroup; average adherence was about 64%.
Eight randomized participants were excluded after randomization, adherence averaged 64%, and the positive interpretation relies on a very small genotype subgroup despite a null overall cognitive result. Water was supplied by Blue Mercury; one author had previously advised the company.
What kind of evidence is this?
Human
Randomized double-blind placebo-controlled parallel clinical study with separate animal experiments
Other neurological conditions
H₂-rich water
Information not yet classified
Some editorial classification fields are still pending. The source-reported outcomes and result are shown below; Hydrogenology does not infer a positive or negative signal from prose automatically.
Methods
Older adults with mild cognitive impairment
81 randomized; 73 analyzed: H₂ water n=35 and placebo n=38
1 year
One 500 mL pouch of hydrogen-rich water daily
H₂ dissolved in water — H₂ only, not Brown’s gas.
More than 0.6 mM dissolved H₂ when supplied.
Identically packaged placebo water, 500 mL/day
Outcomes and reported result
ADAS-cog and cognitive subscales, including exploratory APOE4-carrier analyses
Overall ADAS-cog did not differ significantly between groups. Favorable findings were reported in the small APOE4-carrier subgroup; average adherence was about 64%.
Human dose, methods, full results, funding and conflicts checked in the open-access full text; independent appraisal remains incomplete.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Eight randomized participants were excluded after randomization, adherence averaged 64%, and the positive interpretation relies on a very small genotype subgroup despite a null overall cognitive result. Water was supplied by Blue Mercury; one author had previously advised the company.
Older adults with mild cognitive impairment; the animal component is separate from the human trial.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 29110615 · DOI: 10.2174/1567205014666171106145017
Open-access full text is available through PMC.
Open-access PMC full text and PubMed bibliographic record.
10 August 2026
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