Molecular Hydrogen Positively Affects Physical and Respiratory Function in Acute Post-COVID-19 Patients
Botek M et al. · Int J Environ Res Public Health. 2022;19(4):1992.
Study at a glance
Human
Non-hospitalized, unvaccinated adults tested 21–35 days after acute COVID-19
Nasal-cannula H₂ at 300 mL/min for two 60-minute home sessions daily · 99.99% H₂ source-gas purity according to the generator manual.
Two 60-minute sessions daily for 14 days
Changes favored H₂ for six-minute walk distance, FVC and FEV1. Daily fatigue, sleep, muscle soreness and dyspnea ratings did not differ between groups; oxygen saturation and exertion comparisons were also null.
Single-blind, 50-person short trial with baseline BMI and body-fat imbalance and home self-administration. It concerns early post-acute recovery, not established Long COVID. Authors declared no conflicts.
What kind of evidence is this?
Human
Randomized single-blind placebo-controlled parallel trial
Long COVID
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
Non-hospitalized, unvaccinated adults tested 21–35 days after acute COVID-19
50 participants: 26 men and 24 women
Two 60-minute sessions daily for 14 days
Nasal-cannula H₂ at 300 mL/min for two 60-minute home sessions daily
H₂ alone at high source-gas purity — not Brown’s gas.
99.99% H₂ source-gas purity according to the generator manual.
Ambient air from a modified generator
Outcomes and reported result
Six-minute walk, FVC, FEV1, oxygen saturation, dyspnea, exertion and daily symptom ratings
Changes favored H₂ for six-minute walk distance, FVC and FEV1. Daily fatigue, sleep, muscle soreness and dyspnea ratings did not differ between groups; oxygen saturation and exertion comparisons were also null.
Gas purity, flow, methods, full outcome tables, 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
Single-blind, 50-person short trial with baseline BMI and body-fat imbalance and home self-administration. It concerns early post-acute recovery, not established Long COVID. Authors declared no conflicts.
Clinically stable, non-hospitalized adults 21–35 days after COVID-19 under the study criteria.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 35206179 · DOI: 10.3390/ijerph19041992
Open-access publisher and PMC full texts are available.
Open-access PMC and publisher full texts plus PubMed bibliographic record.
10 August 2026
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