Hydrogen-rich bath with nano-sized bubbles improves antioxidant capacity based on oxygen radical absorbing and inflammation levels in human serum
Tanaka Y, Xiao L, Miwa N. · Medical Gas Research. 2022;12(3):91–99.
Study at a glance
Human
Six healthy volunteers and nine people with heterogeneous inflammatory, connective-tissue or other diseases.
A 200 L bath at 40°C was typically electrolyzed for 60 minutes, followed by a 10-minute bath repeated daily in longer observations. · The apparatus produced approximately 150 µg/L dissolved H₂ after 30 minutes and approximately 250 µg/L after 60 minutes; the article also reports 338–682 µg/L under 120-minute/other measured conditions. Mean bubble diameter was 110±10 nm.
Ten-minute short-term baths; uncontrolled daily use ranged from 9 days to 25 months.
Within the n=3 hydrogen-bath healthy group, antioxidant capacity increased at later measurements, but the article states there was no significant between-group difference versus the n=3 normal-water group. CRP changes and declines in the nine heterogeneous patient observations were uncontrolled; visible symptom changes were descriptive and cannot establish treatment effects.
Extremely small healthy comparison (n=3 per arm), heterogeneous uncontrolled patient cases, variable duration and surrogate/descriptive outcomes. The device was the commercial Lita Life Ver. 2 and one author was affiliated with the Institute for Hydrogen Medicine. Funding was a corporate grant (No. 1705) to the Japanese Center for Anti-Aging Medical Sciences; authors declared no conflict of interest.
What kind of evidence is this?
Human
Exploratory controlled healthy-volunteer experiment plus uncontrolled case series
Immune and inflammatory conditions
Other forms
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
Six healthy volunteers and nine people with heterogeneous inflammatory, connective-tissue or other diseases.
Healthy short-term experiment: 3 normal-water and 3 hydrogen-bath participants. Uncontrolled patient observations: 3 connective-tissue cases followed 9 days–4 months and 6 heterogeneous cases followed 2–25 months.
Ten-minute short-term baths; uncontrolled daily use ranged from 9 days to 25 months.
A 200 L bath at 40°C was typically electrolyzed for 60 minutes, followed by a 10-minute bath repeated daily in longer observations.
H₂ dissolved as nano-bubbles in bath water — topical exposure, not inhaled or swallowed and not Brown's gas.
The apparatus produced approximately 150 µg/L dissolved H₂ after 30 minutes and approximately 250 µg/L after 60 minutes; the article also reports 338–682 µg/L under 120-minute/other measured conditions. Mean bubble diameter was 110±10 nm.
Normal-water bath for the six-person short-term experiment; no parallel controls for the nine patient observations.
Outcomes and reported result
Serum oxygen-radical absorption capacity, C-reactive protein and descriptive photographs/symptoms in selected cases.
Within the n=3 hydrogen-bath healthy group, antioxidant capacity increased at later measurements, but the article states there was no significant between-group difference versus the n=3 normal-water group. CRP changes and declines in the nine heterogeneous patient observations were uncontrolled; visible symptom changes were descriptive and cannot establish treatment effects.
The complete PubMed Central article, participant flow, figures, H₂ and O₂ measurements, within- versus between-group tests, case observations, funding and conflict declaration were checked.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Extremely small healthy comparison (n=3 per arm), heterogeneous uncontrolled patient cases, variable duration and surrogate/descriptive outcomes. The device was the commercial Lita Life Ver. 2 and one author was affiliated with the Institute for Hydrogen Medicine. Funding was a corporate grant (No. 1705) to the Japanese Center for Anti-Aging Medical Sciences; authors declared no conflict of interest.
Exploratory topical-bath observations only; not reliable evidence of clinical efficacy for inflammatory or connective-tissue diseases.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 34854419 · DOI: 10.4103/2045-9912.330692
Free full article on PubMed Central.
PubMed metadata and complete PubMed Central article; full-text extraction checked 8 August 2026.
10 August 2026
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