The Effect of 14-Day Consumption of Hydrogen-Rich Water Alleviates Fatigue but Does Not Ameliorate Dyspnea in Long-COVID Patients: A Pilot, Single-Blind, and Randomized, Controlled Trial
Tan Y et al. · Nutrients. 2024;16(10):1529.
What kind of evidence is this?
Human
Pilot single-blind randomized placebo-controlled trial
Long COVID
H₂-rich water
Not reported in this record.
Not reported in this record.
Methods at a glance
Vaccinated, non-hospitalized adults aged 18–65 with persistent fatigue and dyspnea after COVID-19
55 recruited; 32 randomized and completed (16 per group)
14 days
Freshly prepared hydrogen-rich water, 500 mL in the morning and 500 mL in the evening, consumed within 10 minutes
H₂ dissolved in water — H₂ only, not Brown’s gas.
1,600 ppb dissolved H₂; pH 7.6, oxidation-reduction potential −590 mV and 22 °C reported.
Not applicable — oral water, not gas inhalation.
No O₂ was co-delivered as part of the intervention.
Equal amount of pure placebo water in identical packaging
Outcomes and reported result
Fatigue, dyspnea, 6-minute walk, chair stand, sleep quality and mood scales
Compared with placebo, percent changes favored H₂ water for fatigue (p=0.046), 6-minute walk distance (p<0.001), chair-stand performance (p=0.002) and sleep quality (p=0.012). Dyspnea (p=0.556) and mood scores did not differ significantly.
Methods, full outcome tables, funding and conflict statements checked in the open-access full text; independent risk-of-bias appraisal remains incomplete.
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
Small pilot, single blinding, 14-day intervention, home testing with remote administration, multiple outcomes and a secondary percent-change fatigue finding despite a non-significant group-by-time interaction for the primary FSS model.
Vaccinated, non-hospitalized adults meeting this study’s Long COVID criteria; not hospitalized or medically complex populations.
Cochrane RoB 2 · parallel randomized trial · headline fatigue result
High risk — preliminary for the headline fatigue interpretation
Single blinding, staff administering home assessments knew allocation, and the highlighted fatigue finding comes from a secondary percent-change analysis although the primary group-by-time interaction for FSS was not significant.
Some concerns — Excel random-number generation is described; allocation concealment is not. · Some concerns — participants were blinded, but assessment staff knew group assignment. · Low concern — all 32 randomized participants completed the study. · High risk for subjective fatigue — remotely administered FSS with assessors aware of allocation. · High risk for the headline fatigue result — emphasis on a secondary percent-change analysis despite a non-significant primary interaction.
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: 38794767 · DOI: 10.3390/nu16101529
Open-access publisher and PMC full texts are available.
Open-access publisher full text, PMC record and PubMed bibliographic record.
2026-08-10