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HBOT for Chronic Fatigue (ME/CFS) and Fibromyalgia: What Studies Show

The evidence for hyperbaric oxygen in ME/CFS is thin: no randomised trial yet. Fibromyalgia has more studies, but few controls. What exists and what it means.

Updated September 14, 2026
10 min read
by Hyperbaric.app

This content is for informational purposes only and does not constitute medical advice. Always consult a healthcare professional. Read full disclaimer

The evidence that hyperbaric oxygen therapy (HBOT) helps myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is thin. We could not find a single randomised controlled trial. What exists is two small older studies with conflicting results and a 2026 uncontrolled study of 30 patients in Berlin, most of whom developed ME/CFS after COVID-19.

Fibromyalgia has more research, and two meta-analyses report less pain after HBOT. But most trials compared HBOT with no treatment or delayed treatment rather than with a sham chamber session, so a placebo effect cannot be ruled out. HBOT is not an accepted indication for either condition.

What is ME/CFS?

The US Centers for Disease Control and Prevention (CDC) describes ME/CFS as a serious, often long-lasting illness that affects many parts of the body. It causes severe fatigue that is not improved by rest, problems with thinking and sleep, dizziness and pain. Its hallmark is post-exertional malaise (PEM): symptoms get worse after physical or mental activity, sometimes leaving people in bed for an extended time. CDC estimates that up to 3.3 million people in the United States have ME/CFS, and that about 1 in 4 are confined to bed at some point in their illness.

There is no known cause or cure. The UK's NICE guideline on ME/CFS (2021) says symptoms can be managed but there is currently no cure, and advises against offering graded exercise therapy or any medicine or supplement as a cure. HBOT does not appear among its recommendations.

Is HBOT an accepted treatment for ME/CFS or fibromyalgia?

No. Neither condition is on the Undersea and Hyperbaric Medical Society (UHMS) list of approved indications, and neither is on the European Committee for Hyperbaric Medicine (ECHM) list of accepted indications from its 2016 consensus conference. Clinics that offer HBOT for these conditions are relying on early research, not guidelines. See our guide to accepted HBOT indications for the full lists.

What studies exist for HBOT in ME/CFS?

StudyPatientsProtocolControl groupFinding
Akarsu et al., Turkey (2013)1615 sessions over 3 weeksNoneFatigue and fatigue-related quality of life scores improved
Kim et al., Germany (2026)30 (27 after COVID-19)40 sessions at 2 ATA, spread over 8-16 weeksNone for treatment effectsModest average gain in physical function; 11 of 30 had a clinically meaningful improvement

The 2013 Turkish study

A small study in Undersea and Hyperbaric Medicine gave 16 patients diagnosed with CFS 15 HBOT sessions over three weeks. Fatigue scores and fatigue-related quality of life improved, and the treatment was well tolerated. There was no control group, and the authors wrote that studies with larger samples and control groups were "definitely awaited".

The 2026 Charité study in Berlin

The most detailed study so far was published in the Journal of Translational Medicine by researchers at Charité - Universitätsmedizin Berlin. Thirty adults with ME/CFS received 40 sessions of 100% oxygen at 2 ATA for 90 minutes. To reduce the risk of PEM from travel and sitting upright, the team allowed the course to stretch over 8 to 16 weeks instead of a fixed schedule. Twenty-seven of the 30 patients had developed ME/CFS after COVID-19.

What they found:

  • Physical functioning (the SF-36 questionnaire, scored 0 to 100) rose by an average of 6.3 points by the last session and was 4.5 points above baseline four weeks after treatment.
  • Eleven of the 30 patients (37%) improved by at least 10 points, a common threshold for a clinically meaningful change.
  • Fatigue, pain, processing speed, exercise capacity and grip strength also improved.
  • No patient stopped because of PEM, though a small number stopped early because of pressure problems in the sinuses or middle ear.

The authors are unusually clear about the limits. The study had no sham or untreated control group, so natural fluctuation, regression to the mean and placebo effects may explain some of the changes. They point out that comparison groups in earlier ME/CFS trials improved by roughly 10 to 13 points on the same scale over longer follow-up. Very severely affected, housebound patients were excluded, and the results may not apply to ME/CFS triggered by something other than COVID-19. They also note that before their study only two small ME/CFS studies existed, with conflicting results.

How does this relate to long COVID?

The two conditions overlap. In a 2022 German cohort study of 42 people with persistent moderate to severe fatigue and exertion intolerance six months after COVID-19, 19 met the Canadian Consensus Criteria for ME/CFS. The Charité team describes SARS-CoV-2 as now among the most frequent triggers of ME/CFS.

That is why long COVID research is often quoted to people with ME/CFS. The picture there is mixed. An Israeli sham-controlled trial of 40 sessions found improvements in energy, sleep, cognition and pain, while Swedish and Belgian placebo-controlled trials of 10 sessions found no difference from placebo. The Charité authors also note that only 77% of patients in the Israeli trial reported fatigue at all. Our long COVID article goes through those trials in detail.

Fibromyalgia: more studies, similar weaknesses

Fibromyalgia shares several features with ME/CFS, including fatigue, poor sleep and widespread pain, and has been studied more often.

  • Israel, 2015. A crossover trial in PLoS One included 60 women with fibromyalgia. HBOT was 40 sessions of 100% oxygen at 2 ATA, 90 minutes, five days a week. Symptoms and quality of life improved after HBOT, and brain SPECT scans changed, while no improvement was seen during a no-treatment control period. The comparison was waiting, not a sham session.
  • Canada, 2021. A feasibility study at Toronto General Hospital randomised 18 patients to immediate HBOT or HBOT after a 12-week wait. Seventeen completed it. Both groups improved after HBOT, and the improvement held at 3 months. Side effects included mild middle ear barotrauma in three patients and new short-sightedness in four.
  • Brazil, 2026. The HOTFy trial randomised 56 women to early or delayed HBOT (2.3 ATA, 90 minutes, 32 to 40 sessions) on top of standard care, with blinded assessors. Pain, symptom impact and quality of life improved more while patients were receiving HBOT. After stopping, some scores drifted back towards standard-care levels. About 21% of participants withdrew, mostly for non-compliance or intolerance of the chamber.

Two meta-analyses have pooled these kinds of studies:

  • A 2023 review in BMJ Open of nine studies with 288 patients found that HBOT relieved pain compared with control interventions. Adverse events occurred in 23.8% of patients, and 6.5% withdrew because of them, though none were serious. The authors suggested that pressures below 2.0 ATA might reduce adverse events in fibromyalgia.
  • A 2026 meta-analysis in Reumatologia of five randomised trials with 227 women found greater pain reduction with HBOT, but no significant improvement in quality of life, and called the evidence limited.

The common weakness is the comparison. When patients know they are getting the treatment, expectations and the attention of daily clinic visits can improve how they feel. In a review of unestablished HBOT indications, Mitchell and Bennett point out that in blinded, sham-controlled trials in other chronic conditions, the HBOT and sham groups often both improved, which suggests a placebo or participation effect. Open-label studies without a sham cannot separate those effects from a real benefit.

Practical concerns for people with ME/CFS

  • Energy cost. A standard course means travelling to a clinic up to five days a week for two months. For someone with PEM, the trip can cost more than the session. The Charité team adapted the schedule for this reason, and still excluded housebound patients.
  • Side effects. Middle ear barotrauma is one of the most common side effects of HBOT, and temporary short-sightedness is common after several weeks at 2.0 ATA or higher. Serious problems such as oxygen toxicity seizures are rare. Read more in our guide to HBOT side effects.
  • Chamber type. The studies above used medical chambers at 2.0 ATA or more with 100% oxygen. Soft-shell "mild" chambers at around 1.3 ATA were not tested in them, and the UHMS considers mild hyperbaric treatment unproven. See our chamber types guide.
  • Cost. Because these are not accepted indications, insurance is unlikely to pay (see our HBOT insurance coverage guide). Ask for the total price of the full course in writing.

Questions to ask before starting

  1. Which study is your protocol based on, and what pressure and oxygen level will you use?
  2. Can the schedule be adapted if I crash after sessions?
  3. How will we measure whether it is helping, and when do we stop if it is not?
  4. Who supervises treatment, and are they experienced with ME/CFS or fibromyalgia?
  5. Is there a clinical trial I could join instead?

Keep your own doctor involved. For help comparing providers, read how to choose an HBOT clinic, and use the directory to find a hyperbaric clinic near you.

Sources

This article is for information only and is not medical advice. ME/CFS and fibromyalgia should be managed with a qualified healthcare professional, and whether HBOT is appropriate for you should be decided with a physician.

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