Hyperbaric Oxygen
Hyperbaric Oxygen · Pressurized O2 Therapy
Evidence grade 3 of 5, Mixed. Read how the Atlas grades evidence.
40 human trials, about 900 studies, RCTs typically 30 to 75 participants each; thousands treated in wound registries. The written rationale for this grade is still being prepared.
- FDA
- FDA clears HBOT chambers as Class II devices via 510(k). UHMS lists ~14 to 17 approved indications (decompression sickness, CO poisoning, gas gangrene, radiation injury, diabetic foot ulcers, sudden hearing loss). Anti-aging, autism, long-COVID and sports recovery are off-label; FDA has warned that unproven uses can delay real care.
- WADA
- Permitted. WADA briefly listed HBOT around 2006 but reclassified supplemental oxygen and hyperbaric tents as allowed (2009). Only blood doping and artificial manipulation of oxygen transport remain banned, not breathing oxygen in a chamber.
Reference only. Not medical advice.
What can go wrong
The defining danger is fire. A chamber full of oxygen can turn a single spark, a lighter, a battery, or an electronic device into a flash fire, and inside a hyperbaric chamber such a fire is almost always fatal. Two people died this way in the United States in 2025, one a child. Pressure changes cause ear and sinus barotrauma, and high-dose oxygen can trigger seizures from oxygen toxicity and temporary nearsightedness. Home soft-shell chambers sold for anti-aging or recovery run at low pressure and sit in a regulatory gray zone, untested for those claims. HBOT for an approved indication belongs at an accredited hyperbaric facility, overseen by a physician, with proper grounding and safety protocols, not in a wellness storefront or a tent in a spare room. Anyone weighing HBOT for a serious or off-label condition, and any decision involving a child, pregnancy, or a mental-health concern, should work through a qualified medical provider before starting.
Hyperbaric oxygen therapy has a patient breathe near-100 percent oxygen at 2 to 3 atmospheres, dissolving far more oxygen into plasma than ordinary breathing allows. The evidence divides cleanly by what the chamber is being used for. The FDA clears hyperbaric chambers as Class II devices for 13 specific conditions, and the Undersea and Hyperbaric Medical Society recognizes roughly 15 to 16. The firmest ground covers decompression sickness, air or gas embolism, carbon monoxide poisoning, gas gangrene, delayed radiation injury, and non-healing diabetic foot ulcers. Weaver's 2002 New England Journal of Medicine trial found hyperbaric oxygen reduced cognitive problems after carbon monoxide poisoning, and a Cochrane review (Kranke 2015) found faster diabetic-ulcer healing at six weeks, though no reduction in amputations. The wellness story is thinner. Efrati's group reported telomere lengthening and fewer senescent cells after 60 sessions, but that 2020 trial enrolled 35 people, had no control group, measured cells rather than health, and came from investigators tied to a company selling the programs. The same group's post-COVID and cognition trials are sham-controlled but small and single-center, and independent replication is scarce. Autism, cancer, and Alzheimer's claims have no credible support, and the FDA has cautioned that believing HBOT is proven for such uses can lead people to delay treatments that work. Safety is the sharp edge: an oxygen-saturated chamber is a fire hazard, and 2025 brought two fatal US chamber fires. Home soft-shell units run near 1.3 atmospheres, a fraction of clinical pressure, and sit in a regulatory gray zone for the longevity claims marketed around them.
Pressurized oxygen with ~14 solid medical uses; the home soft-chamber wellness boom rests on far thinner evidence
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
What people get wrong
Often saidHyperbaric oxygen reverses aging.
ActuallyThe most cited support is Hachmo and Efrati's 2020 trial in Aging, which reported telomere lengthening up to about 38 percent and fewer senescent T-cells after 60 sessions. It enrolled 35 people, completed 30, had no control group, measured blood cells rather than any health outcome, and was authored partly by staff and a shareholder of a company selling HBOT programs. The authors themselves list the small size and lack of a control group as limitations, so it is a hypothesis, not evidence that anyone ages more slowly.
Often saidA home chamber gives you the same therapy as a hospital.
ActuallyHome soft-shell units generally run near 1.3 atmospheres, often on room air, while UHMS-approved and FDA-cleared protocols use 2 to 3 atmospheres with near-100 percent oxygen. That is a fundamentally different dose, and the clinical evidence for HBOT was generated almost entirely at the higher pressures.
Often saidThe FDA has approved HBOT for autism, cancer, and Alzheimer's.
ActuallyThe FDA clears hyperbaric chambers for 13 specific conditions and lists none of these among them. The agency has cautioned that patients may wrongly believe chambers are proven safe and effective for uncleared uses, which can lead them to delay or forgo proven care.
Often saidOxygen is harmless, so HBOT is risk-free.
ActuallyAn oxygen-saturated chamber is highly flammable. In 2025 a flash fire killed a 5-year-old in Troy, Michigan, and another killed a physical therapist in Lake Havasu City, Arizona. Barotrauma to ears and sinuses and oxygen-toxicity seizures are also recognized risks.
Who profits, and who pushes back
U.S. FDA
Patients may incorrectly believe that these devices have been proven safe and effective for uses not cleared by FDA, which may cause them to delay or forgo proven medical therapies.
Cochrane (Kranke and colleagues)
Hyperbaric oxygen therapy significantly improved the ulcers healed in the short term but not the long term, and the trials had various flaws in design and reporting.
Dana Nessel, Michigan Attorney General
A single spark it appears ignited into a fully involved fire that claimed Thomas's life within seconds.
Shai Efrati
Sells this. Has a commercial interest in a product sold as this compound, as of July 2026.
Lead author of the aging, cognition and post-COVID trials; affiliated with Aviv Clinics, which sells HBOT programs.
Aviv Clinics
Sells this. Has a commercial interest in a product sold as this compound, as of July 2026.
Markets longevity and cognitive programs built on the Efrati trials; direct financial interest.
Bryan Johnson
Publicly promotes personal HBOT use; no disclosed payment but heavily self-promotional.
UHMS
Maintains the approved-indications list and cautions against unproven uses.
Where the research comes from
| Place | Share of published research |
|---|---|
| North America | 40% |
| Asia | 27% |
| Europe | 21% |
| Middle East | 8% |
| Rest of world | 4% |
Research published from: Global; major centers in USA, Israel, China, Japan, UK.
How we got here
The lineage runs from Nathaniel Henshaw's 1662 pressurized domicilium in England, built before oxygen had even been identified as an element, through the compressed-air baths that spread across Europe in the 1700s and 1800s. Paul Bert's 1878 work in France tied oxygen and pressure to both decompression sickness and oxygen toxicity, and John Scott Haldane, a Scottish physiologist, formalized staged decompression for divers around 1905. Naval and diving medicine drove practical chambers through the early twentieth century, with Albert Behnke applying hyperbaric oxygen to decompression sickness in the late 1930s. The Dutch surgeon Ite Boerema, often called the father of modern hyperbaric medicine, demonstrated its surgical use under pressure in the 1950s and 1960s. The Undersea Medical Society, later the Undersea and Hyperbaric Medical Society, formed in 1967 and built the approved-indication and accreditation framework that governs clinical use today, alongside which the consumer wellness market later grew.
- 1662Nathaniel Henshaw builds the pressurized domicilium chamber in England
- 1878Paul Bert links oxygen, pressure, and decompression sickness
- c. 1905John Scott Haldane formalizes staged diver decompression
- 1937Albert Behnke uses hyperbaric oxygen for decompression sickness
- 1950sIte Boerema applies hyperbaric oxygen in surgery in the Netherlands
- 1967Undersea Medical Society, later UHMS, is founded
- 2002Weaver NEJM trial supports HBOT for carbon monoxide cognitive sequelae
- 2015Cochrane (Kranke) finds diabetic-ulcer healing at 6 weeks, none at 12 months
- 2020Efrati group reports telomere lengthening in a small uncontrolled aging trial
- 2021FDA reiterates 13 cleared uses and cautions about unproven claims
- 2022Zilberman-Itskovich publishes a sham-controlled post-COVID RCT
- 2025Two fatal US chamber fires, a 5-year-old in Michigan and a clinician in Arizona, spur state legislation
At a glance
- Approved indications
- ~14 to 17 conditions recognized by UHMS, cleared by FDA
- Wellness chamber pressure
- Home soft shells run ~1.3 ATA vs medical 2 to 3 ATA
- Efrati aging trial
- 60 sessions, telomeres up to +38%, senescent cells up to -37%
- Primary hazard
- Oxygen-fueled fire; home and clinic chamber deaths in 2025
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Hyperbaric Oxygen. A short entry is not a safe entry.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
Sources
FDA clears hyperbaric chambers as Class II devices for exactly 13 conditions and warns HBOT is not proven for cancer, autism, Alzheimer's, or Lyme disease
U.S. Food and Drug Administration, Hyperbaric Oxygen Therapy: Get the Facts
Detailed enumeration of the 13 FDA-cleared HBOT conditions and Class II device status, including the addition of hearing loss and vision loss
Intellicure, The FDA Updates Its List of Conditions for Which HBOT Chambers Are Cleared for Use
UHMS recognizes roughly 15 to 16 approved hyperbaric indications, listed in full
Three hyperbaric oxygen treatments reduced cognitive sequelae 6 weeks and 12 months after acute carbon monoxide poisoning in a double-blind randomized trial
HBOT improved diabetic foot ulcer healing at 6 weeks but not at 12 months and did not reduce major amputation
The aging trial enrolled 35 people (30 completed), had no control group, reported telomere lengthening up to about 38% and reduced senescent cells, and disclosed AVIV Scientific conflicts
Sham-controlled double-blind RCT of 73 post-COVID patients reported cognitive and psychological improvement after 40 HBOT sessions
5-year-old Thomas Cooper killed in a hyperbaric chamber flash fire in Troy, Michigan, on January 31, 2025; four staff charged including second-degree murder counts
The child was being treated off-label for ADHD and sleep apnea at a center advertising plans for over 100 conditions versus 13 FDA-approved uses
Detroit News, Cooper's family sues Oxford Center over hyperbaric chamber death
Physical therapist Walter Foxcroft, 43, died in a hyperbaric chamber flash fire in Lake Havasu City, Arizona, July 2025, the second US chamber fire death that year
CBS News, Physical therapist dies inside hyperbaric oxygen chamber at his Arizona facility
Home soft-shell chambers run near 1.3 ATA and fall into a regulatory gray zone, sold direct to consumers without prescription for wellness claims
Peak Primal Wellness, Hyperbaric Chambers: Soft and Hard Shell, 1.3 to 2.0 ATA HBOT
In late December 2025 the FDA retired a consumer webpage on unproven autism products that had cited HBOT, described by HHS as routine removal of dated content
Disability Scoop, FDA Pulls Warning About Potentially Dangerous Autism Therapies