Hydrogen and Fatigue: What Studies Show, From Exercise to ME/CFS

By Hydrogen Studies Editorial Team · Updated

Hydrogen Studies is funded by Echo Technologies LLC, which sells hydrogen water products. Echo doesn't decide which studies we cover or how we describe them — see our editorial policy.

Evidence at a glance: very low for chronic fatigue syndrome (ME/CFS), long COVID and cancer-related fatigue. Moderate that hydrogen slightly reduces how tiring exercise feels in healthy adults.

"Fatigue" means two different things in hydrogen research, and the evidence for each is very different. About 40 human studies in our database mention fatigue. Roughly 16 tested exercise in healthy adults or athletes. About 20 involved people with a diagnosed illness, and most of those were single-patient case reports or small pilot studies.

Fatigue during exercise in healthy adults

Most of the controlled trials are here. A 2023 meta-analysis pooled 19 randomized studies with 402 healthy adults. Hydrogen slightly lowered ratings of perceived effort and blood lactate, but it didn't change VO2max or endurance. A 2024 meta-analysis of 27 publications and 597 adults found the same pattern, with no gain in strength. In one of the largest single studies, 99 untrained and 60 trained adults drank 500 mL of hydrogen water (0.8–1.0 ppm) shortly before cycling and reported less fatigue. It drew a published critique from other researchers.

Doses studied: drinking water with 0.5–5.9 ppm hydrogen, or inhaled gas at 1–68% hydrogen, given as a single dose or daily for 2–14 days. In the 2023 analysis, perceived effort dropped after a single pre-exercise dose but not in the two studies that used several days of intake. The effect is on how tired people felt, not on how far or fast they went. See the exercise fatigue section of our benefits guide and our exercise recovery hub.

ME/CFS (chronic fatigue syndrome)

There is no large trial. A 2026 review, written in part by the team that ran them, describes three small pilot trials of hydrogen-rich water made from tablets. The only one with a placebo group (4 weeks, about 12 mg of hydrogen a day) found no benefit, and about half of participants had temporary moderate-to-severe side effects such as headaches and stomach upset. Two later trials without a placebo group, lasting 8 and 16 weeks, reported improvements in self-rated fatigue and physical function. We couldn't find those trials indexed in PubMed.

Separately, four case reports described symptom relief in people with ME/CFS who inhaled hydrogen gas for 3–6 hours a day over 8–20 weeks. There was no comparison group, and four of the five authors work for the company that makes the inhaler used.

Long COVID, cancer and dialysis fatigue

  • Long COVID. In a single-blind trial, 32 adults still fatigued and breathless about a month after COVID-19 drank 1 liter a day of 1.6 ppm hydrogen-rich water or plain water for 14 days. The main analysis found no significant difference in fatigue between groups; a secondary analysis of percentage change favored hydrogen. Breathlessness didn't improve.
  • Cancer. In a randomized trial of 49 patients having radiotherapy for liver tumors, 6 weeks of hydrogen-rich water (about 1.1–1.3 ppm, 1.5–2 liters a day) improved overall quality-of-life scores, but fatigue scores didn't differ from placebo. An uncontrolled report of 82 people with advanced cancer who inhaled hydrogen described less fatigue, with no comparison group.
  • Dialysis. In 81 hemodialysis patients, fatigue fell among the most fatigued after 12 months of hydrogen-enriched dialysis fluid, with no control group. See our kidney health hub.

What animal studies suggest (not human evidence)

Mice forced to swim every day for 4 weeks swam longer and had lower lactate and inflammation markers when they drank hydrogen water. That models repeated exhausting exercise, not the illness-related fatigue of ME/CFS.

What we don't know

  • Whether hydrogen helps ME/CFS in a large, double-blind, placebo-controlled trial
  • Whether the small drop in exercise effort lasts, or matters outside the lab
  • Whether hydrogen changes everyday tiredness in healthy people who aren't exercising
  • Which dose, if any, helps, and whether high tablet doses cause more side effects

Fatigue that lasts for weeks deserves a medical checkup. If you have ME/CFS, long COVID or cancer, talk to your doctor before adding anything, and don't replace your care.

Drafted with AI assistance and checked against each linked source by our editorial team. General information, not medical advice.

Frequently asked questions

Does hydrogen water help with chronic fatigue syndrome (ME/CFS)?

It hasn't been shown to. The only placebo-controlled trial we know of in ME/CFS, a small 4-week pilot using about 12 mg of hydrogen a day from tablets, found no benefit, and about half of participants had temporary side effects such as headaches and stomach upset. Two later pilot trials without a placebo group, and four case reports, described improvements in self-rated symptoms. That is very low-certainty evidence, and hydrogen is not a treatment for ME/CFS.

Does hydrogen water reduce tiredness during exercise?

Slightly, in healthy adults. Two meta-analyses of randomized trials, with 402 and 597 participants, found that hydrogen made exercise feel a little easier and lowered blood lactate, but it did not improve VO2max, endurance or strength. Most trials were small and short, often a single drink of 0.5 to 5.9 ppm hydrogen water shortly before exercise.

Can hydrogen water help with long COVID fatigue?

The evidence is very limited. In one trial, 32 adults still fatigued about a month after COVID-19 drank 1 liter a day of hydrogen-rich water or plain water for 14 days. The main analysis found no significant difference in fatigue between the groups; a secondary analysis favored hydrogen, and breathlessness did not improve. Larger, double-blind trials are needed.

Does hydrogen water give you more energy?

There's no good evidence that it boosts everyday energy in healthy people who aren't exercising. The measured effects are on how hard exercise feels during short lab tests. Fatigue that lasts for weeks can have many medical causes, so it deserves a checkup rather than a supplement.

Sources

  1. Zhou K, Liu M, Wang Y, et al. Effects of molecular hydrogen supplementation on fatigue and aerobic capacity in healthy adults: a systematic review and meta-analysis. Frontiers in Nutrition. 2023;10:1094767. PubMed · Our summary
  2. Zhou K, Shang Z, Yuan C, et al. Can molecular hydrogen supplementation enhance physical performance in healthy adults? A systematic review and meta-analysis. Frontiers in Nutrition. 2024;11:1387657. PubMed · Our summary
  3. Mikami T, Tano K, Lee H, et al. Drinking hydrogen water enhances endurance and relieves psychometric fatigue: a randomized, double-blind, placebo-controlled study. Canadian Journal of Physiology and Pharmacology. 2019;97(9):857-862. PubMed · Our summary
  4. Falster C, Korfitzen S, Herold M, Lindebjerg J, Elsøe M. Discussion: Drinking hydrogen water enhances endurance and relieves psychometric fatigue: a randomized, double-blind, placebo-controlled study. Canadian Journal of Physiology and Pharmacology. 2021;99(10):1114-1115. PubMed · Our summary
  5. Friedberg F, LeBaron TW. Molecular hydrogen as a treatment for ME/CFS: a mini-review of clinical evidence and mechanistic rationale. Frontiers in Medicine. 2026;13:1760210. PubMed · Our summary
  6. Hirano SI, Ichikawa Y, Sato B, Takefuji Y, Satoh F. Successful treatment of myalgic encephalomyelitis/chronic fatigue syndrome using hydrogen gas: four case reports. Medical Gas Research. 2024;14(2):84-86. PubMed · Our summary
  7. Tan Y, Xie Y, Dong G, et al. 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. Nutrients. 2024;16(10):1529. PubMed · Our summary
  8. Kang KM, Kang YN, Choi IB, et al. Effects of drinking hydrogen-rich water on the quality of life of patients treated with radiotherapy for liver tumors. Medical Gas Research. 2011;1(1):11. PubMed · Our summary
  9. Chen JB, Kong XF, Lv YY, et al. "Real world survey" of hydrogen-controlled cancer: a follow-up report of 82 advanced cancer patients. Medical Gas Research. 2019;9(3):115-121. PubMed · Our summary
  10. Nakayama M, Watanabe K, Sato E, et al. Hemodialysis employing molecular hydrogen (H2) enriched dialysis solution may improve dialysis related fatigue through impact on energy metabolism. Scientific Reports. 2025;15(1):5039. PubMed · Our summary
  11. Ara J, Fadriquela A, Ahmed MF, et al. Hydrogen water drinking exerts antifatigue effects in chronic forced swimming mice via antioxidative and anti-inflammatory activities. BioMed Research International. 2018;2018:2571269. PubMed · Our summary

Research Studies

65 studies in our database.

Read the full guide: Does hydrogen water reduce exercise fatigue? From our evidence-graded benefits guide

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