Hydrogen-oxygen mixture inhalation as an adjunctive treatment to home-based exercise in older patients with knee osteoarthritis
Wang C et al. · Front Pharmacol. 2025;16:1505922.
Study at a glance
Human
Older adults with knee osteoarthritis living in a retirement community
Nasal inhalation of 2.0 L/min H₂ plus 1.0 L/min O₂ for 60 minutes daily, alongside home exercise · Generator output was 2:1 H₂:O₂, approximately 66.7% H₂ and 33.3% O₂.
Inhalation for 60 minutes daily during the first 2 weeks; follow-up through week 12
The week-12 between-group WOMAC difference was not significant and did not reach the minimum clinically important difference. Temporary early differences were reported; sustained objective-function and quality-of-life benefits were not established.
Open-label adjunctive study without placebo gas. The principal week-12 comparison was null and below the clinical-importance threshold; early effects were not sustained. Public funding was reported.
What kind of evidence is this?
Human
Open-label randomized trial with blinded endpoint assessment
Musculoskeletal and pain research
Inhaled H₂
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
Older adults with knee osteoarthritis living in a retirement community
121 participants; mean age 81.2 years; 80.2% women
Inhalation for 60 minutes daily during the first 2 weeks; follow-up through week 12
Nasal inhalation of 2.0 L/min H₂ plus 1.0 L/min O₂ for 60 minutes daily, alongside home exercise
Brown’s gas / oxyhydrogen — H₂ and O₂ co-delivered.
Generator output was 2:1 H₂:O₂, approximately 66.7% H₂ and 33.3% O₂.
2,000 mL/min H₂, directly reported.
1,000 mL/min O₂, directly reported.
The same 12-week home exercise and health-education program without gas inhalation
Outcomes and reported result
WOMAC, chair stand, timed up-and-go, quality of life, exercise adherence, inflammatory markers and adverse events
The week-12 between-group WOMAC difference was not significant and did not reach the minimum clinically important difference. Temporary early differences were reported; sustained objective-function and quality-of-life benefits were not established.
Gas flow, full methods, results, funding and conflicts checked in the open-access full text; independent appraisal remains incomplete.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Open-label adjunctive study without placebo gas. The principal week-12 comparison was null and below the clinical-importance threshold; early effects were not sustained. Public funding was reported.
Very old adults with knee osteoarthritis participating in a home-exercise program.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 39950118 · DOI: 10.3389/fphar.2025.1505922
Open-access full text is available through PMC and Frontiers.
Open-access PMC and Frontiers full texts plus PubMed record.
10 August 2026
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