Hydrogen-rich water for improvements of mood, anxiety, and autonomic nerve function in daily life
Mizuno K et al. · Med Gas Res. 2017;7(4):247–255.
Study at a glance
Human
Healthy adult volunteers aged 20–49 years
Hydrogen-rich water, 300 mL twice daily · 0.8–1.2 ppm dissolved H₂ in 300 mL aluminum pouches.
4 weeks per condition with a 4-week washout
Change ratios for K6 mood/anxiety score and resting sympathetic activity were lower after H₂ water. Many other questionnaire and biological outcomes did not show clear between-condition differences.
Small healthy-volunteer crossover study, five exclusions from analysis, many outcomes and subjective scales. The corresponding author received funding from the water supplier Melodian Corporation.
What kind of evidence is this?
Human
Randomized double-blind placebo-controlled two-period crossover study
Sleep and mood research
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
Healthy adult volunteers aged 20–49 years
31 randomized; 26 analyzed
4 weeks per condition with a 4-week washout
Hydrogen-rich water, 300 mL twice daily
H₂ dissolved in water — H₂ only, not Brown’s gas.
0.8–1.2 ppm dissolved H₂ in 300 mL aluminum pouches.
Identically packaged placebo mineral water without H₂
Outcomes and reported result
Fatigue, mood, anxiety, depression, sleep questionnaires, autonomic measures, cognitive testing and blood markers
Change ratios for K6 mood/anxiety score and resting sympathetic activity were lower after H₂ water. Many other questionnaire and biological outcomes did not show clear between-condition differences.
Dose, methods, main results, registration, funding and conflicts checked in the free full text; independent appraisal remains incomplete.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Small healthy-volunteer crossover study, five exclusions from analysis, many outcomes and subjective scales. The corresponding author received funding from the water supplier Melodian Corporation.
Healthy adults under the reported four-week drinking protocol; not people with a diagnosed mood or sleep disorder.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 29497485 · DOI: 10.4103/2045-9912.222448
Open-access full text is available through PMC.
Open-access PMC full text and PubMed bibliographic record.
10 August 2026
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