Effects of molecular hydrogen-dissolved alkaline electrolyzed water on intestinal environment in mice
Higashimura Y, Baba Y, Inoue R, Takagi T, Uchiyama K, Mizushima K, Hirai Y, Ushiroda C, Tanaka Y, Naito Y. · Medical Gas Research. 2018;8(1):6–11.
Study at a glance
Preclinical
Five-week-old male C57BL/6N mice after a one-week acclimatization period.
Free access to alkaline electrolyzed water for four weeks. · Water contained 0.32 ppm H₂ at pH 9.90 and was supplied in downward-pointing aluminum pouches to limit H₂ loss.
Four weeks of ad-libitum drinking-water exposure.
LDL cholesterol and ALT were lower, cecal-content weight and three organic acids were higher, and 20 bacterial taxa differed with alkaline H₂ water. Body, liver and adipose weights and several other serum/organic-acid measures did not differ. The design cannot separate dissolved H₂ from the water's marked pH difference.
Very small male-mouse study, four-week exposure, ad-libitum dose not quantified, H₂ and pH effects confounded, many microbial taxa tested and unexplained reduction from eight to seven observations in several analyses. Public/industry-linked research funds supported the work; one author was a salaried Panasonic employee and the apparatus was manufactured by Panasonic.
What kind of evidence is this?
Preclinical
Randomized two-group mouse drinking-water and gut-microbiome experiment
Gastrointestinal health
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
Five-week-old male C57BL/6N mice after a one-week acclimatization period.
16 mice randomized, n=8 per group. Several organic-acid and sequencing figures report n=7 per group without explaining the missing observations.
Four weeks of ad-libitum drinking-water exposure.
Free access to alkaline electrolyzed water for four weeks.
H₂ dissolved in alkaline electrolyzed drinking water — H₂ only, not Brown's gas and not inhalation.
Water contained 0.32 ppm H₂ at pH 9.90 and was supplied in downward-pointing aluminum pouches to limit H₂ loss.
Normal drinking water containing 0.00 ppm H₂ at pH 6.83.
Outcomes and reported result
Body and tissue weights, cecal-content weight, serum lipids/liver enzymes/glucose, cecal short-chain fatty acids and fecal 16S microbiome composition.
LDL cholesterol and ALT were lower, cecal-content weight and three organic acids were higher, and 20 bacterial taxa differed with alkaline H₂ water. Body, liver and adipose weights and several other serum/organic-acid measures did not differ. The design cannot separate dissolved H₂ from the water's marked pH difference.
The complete free PMC article, tables and figures were checked for randomization, group size, H₂/pH specification, positive and null metabolic/organic-acid outcomes, sequencing samples, funding and conflicts.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Very small male-mouse study, four-week exposure, ad-libitum dose not quantified, H₂ and pH effects confounded, many microbial taxa tested and unexplained reduction from eight to seven observations in several analyses. Public/industry-linked research funds supported the work; one author was a salaried Panasonic employee and the apparatus was manufactured by Panasonic.
Gut microbiota and metabolic markers in healthy mice; it does not establish gastrointestinal or metabolic benefit in people.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 29770190 · DOI: 10.4103/2045-9912.229597
Free full article in PubMed Central.
Complete PMC article and PubMed metadata; full-text extraction checked 9 August 2026.
10 August 2026
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