Molecular hydrogen inhalation modulates resting metabolism in healthy females: findings from a randomized, double-blind, placebo-controlled crossover study.
Pavel Grepl, Michal Botek, Jakub Krejčí, Andrew McKune · Medical gas research · 2025
Research-use notice
Independent study record
Each H2HUBB study page organizes source-linked research details for educational use. Interpretation should remain proportional to the study design, population, controls, and limitations.
H2HUBB TAKEAWAY
In Twenty, physically active female participants aged 22, compared with placebo (ambient air), molecular hydrogen inhalation significantly decreased respiratory exchange ratio and ventilation across all intervals. These findings add human evidence supporting molecular hydrogen's therapeutic potential across the specific human outcomes evaluated in this study.
What the Findings Mean
H2HUBB reviewed how inhaled hydrogen gas affected the outcomes measured in Twenty, physically active female participants aged 22. Compared with placebo (ambient air), molecular hydrogen inhalation significantly decreased respiratory exchange ratio and ventilation across all intervals.
What the Researchers Studied
The researchers studied Twenty, physically active female participants aged 22. The study used a randomized, double-blind, placebo-controlled, crossover human clinical trial. The comparison condition was placebo.
What Effects Did Molecular Hydrogen Have?
Source-reported hydrogen concentration: 99.8% source-reported H₂ gas concentration; Source-reported hydrogen exposure: 99.8% source-reported H₂ gas concentration; 300 mL/min H₂ flow; via nasal cannula; H2HUBB estimated inhaled H₂ concentration: approximately 1.0–1.3% under standard resting adult assumptions from the source-reported 0.3 L/min pure-H₂ flow; reported treatment duration: 60 minutes. Compared with placebo (ambient air), molecular hydrogen inhalation significantly decreased respiratory exchange ratio and ventilation across all intervals. The authors concluded that in conclusion, 60 minutes of resting molecular hydrogen inhalation significantly increased resting fat oxidation, as evidenced by decreased respiratory exchange ratio, particularly in individuals with higher body fat percentages. The observed decrease in RER may suggest an influence of molecular hydrogen on metabolic processes towards an increased preference for ATP production through oxidative metabolism using lipids at the expense of carbohydrates.
Why These Findings Matter
These findings add human evidence supporting molecular hydrogen's therapeutic potential across the specific human outcomes evaluated in this study and contribute to the growing body of molecular-hydrogen research.
How Strong Is This Evidence?
This is human clinical evidence from a randomized, double-blind, placebo-controlled, crossover human clinical trial. H2HUBB interprets the findings in the context of the study design, sample, comparator, and measured outcomes rather than using one publication as a verdict on hydrogen therapy.
Technical Study Details
H2HUBB classifies this publication as human clinical study with human clinical evidence. The research population or model was Twenty, physically active female participants aged 22. The reported sample size was 24. The study used a randomized, double-blind, placebo-controlled, crossover human clinical trial. The hydrogen delivery method was inhaled hydrogen gas. The source-reported hydrogen concentration was 99.8% source-reported H₂ gas concentration. H2HUBB estimated inhaled H₂ concentration: approximately 1.0–1.3% under standard resting adult assumptions from the source-reported 0.3 L/min pure-H₂ flow. This is a calculated estimate, not a directly measured concentration, and actual inhaled H₂ varies with breathing pattern, ventilation, cannula capture, and gas losses. The reported treatment duration was 60 minutes.
Limitations and Safety
Reported limitations: CONSORT 2010 checklist of information to include when reporting a randomised trial* Section/Topic Item No Checklist item Reported on page No Title and abstract 1a Identification as a randomised trial in the title 1 1b Structured summary of trial design, methods, results, and conclusions (for specific guidance see CONSORT for abstracts) 1 Introduction Background and objectives 2a Scientific background and explanation of rationale 1, 2 2b Specific objectives or hypotheses 2 Methods Trial design 3a Description of trial design (such as parallel, factorial) including allocation ratio 2 3b Important changes to methods after trial commencement (such as eligibility criteria), with reasons No change Participants 4a Eligibility criteria for participants 2 4b Settings and locations where the data were collected 2 Interventions 5 The interventions for each group with sufficient details to allow replication, including how and when they were actually administered 3 Outcomes 6a Completely defined pre-specified primary and secondary outcome measures, including how and when they were assessed 3 6b Any changes to trial outcomes after the trial commenced, with reasons No change Sample size 7a How sample size was determined 4 7b When applicable, explanation of any interim analyses and stopping guidelines Not applicable Randomisation: Sequence generation 8a Method used to generate the random allocation sequence 2 8b Type of randomisation. Details of any restriction (such as blocking and block size) 2 Allocation concealment mechanism 9 Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned 2 Implementation 10 Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions No reported Blinding 11a If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how 2 11b If relevant, description of the similarity of interventions 3 Statistical methods 12a Statistical methods used to compare groups for primary and secondary outcomes 3, 4 12b Methods for additional analyses, such as subgroup analyses and adjusted analyses 4 Results Participant flow (a diagram is strongly recommended) 13a For each group, the numbers of participants who were randomly assigned, received intended treatment, and were analysed for the primary outcome 2 13b For each group, losses and exclusions after randomisation, together with reasons 2 Recruitment 14a Dates defining the periods of recruitment and follow-up 2 14b Why the trial ended or was stopped 2 Baseline data 15 A table showing baseline demographic and clinical characteristics for each group 2 Numbers analysed 16 For each group, number of participants (denominator) included in each analysis and whether the analysis was by original assigned groups 2 Outcomes and estimation 17a For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% confidence interval) 4, 5 17b For binary outcomes, presentation of both absolute and relative effect sizes is recommended Not applicable Ancillary analyses 18 Results of any other analyses performed, including subgroup analyses and adjusted analyses, distinguishing pre-specified from exploratory 6 Harms 19 All important harms or unintended effects in each group (for specific guidance see CONSORT for harms) No harms Discussion Limitations 20 Trial limitations, addressing sources of potential bias, imprecision, and, if relevant, multiplicity of analyses 7 Generalisability 21 Generalisability (external validity, applicability) of the trial findings 7 Interpretation 22 Interpretation consistent with results, balancing benefits and harms, and considering other relevant evidence 6, 7 Other information Registration 23 Registration number and name of trial registry Not available Protocol 24 Where the full trial protocol can be accessed, if available Not available Funding 25 Sources of funding and other support (such as supply of drugs), role of funders 1 Citation: Schulz KF, Altman DG, Moher D, for the CONSORT Group.
Original Study and H2HUBB Research Context
H2HUBB presents this source-grounded research record as one contribution to the broader molecular-hydrogen evidence base.