Effects of Intestinal Bacterial Hydrogen Gas Production on Muscle Recovery following Intense Exercise in Adult Men: A Pilot Study.
Eda N, Tsuno S, Nakamura N, Sone R, Akama T, Matsumoto M. · Nutrients. 2022;14:4875.
What kind of evidence is this?
Human
Double-blind randomized crossover pilot study
Exercise and recovery
Other forms
Mixed exploratory human signal.
Exercise-related functional, subjective and biomarker outcomes.
Methods at a glance
Healthy adult men able to produce breath hydrogen after the test product.
8 participants analyzed after exclusion of non-hydrogen producers.
Acute crossover exercise trials with post-exercise follow-up.
Hydrogen-producing milk containing galacto-oligosaccharide, maltitol and glucomannan, taken four hours before intense exercise.
Endogenous intestinal hydrogen generated by bacterial fermentation; not Brown's gas.
Breath hydrogen increased after the fermentable-ingredient product; no isolated molecular-H2 dose was administered.
Not applicable — oral food ingredients.
No oxygen was co-delivered.
Matched placebo milk in crossover order.
Outcomes and reported result
Breath hydrogen, oxidative and lactate markers, subjective recovery, muscle-damage markers, energy expenditure and microbiome composition.
Breath hydrogen and selected oxidative, lactate and subjective recovery measures changed; objective muscle-damage, energy-expenditure and microbiome-composition outcomes did not clearly differ.
The full article, crossover methods, exclusions, funding and significant and null outcomes were checked.
A reported association, difference or mechanism is not automatically a clinical benefit. Null findings, outcome type, study design and precision all matter.
Cautions and applicability
Eight analyzed participants and a multi-ingredient product; effects cannot be attributed specifically to endogenous hydrogen.
Healthy adult male hydrogen producers under one acute exercise protocol.
Cochrane RoB 2 — preliminary
Some concerns
Randomized crossover design, but post-randomization exclusion and very small sample create concerns.
Randomization reported; concealment not fully established · Deviations cannot be excluded · Available-case reporting checked · Outcome measurement varies by endpoint · No outcome-level protocol comparison completed
No single-study GRADE certainty rating is assigned. Certainty is assessed by important outcome across a complete eligible evidence set, not by attaching a final grade to one source.
Sources and record status
PMID: 36432562 · DOI: 10.3390/nu14224875
Free full article in PubMed Central.
PubMed record and PubMed Central full text; extraction checked 9 August 2026.
2026-08-10