Hyperbaric Oxygen Therapy (HBOT): The Complete Evidence-Based Guide

Hyperbaric oxygen therapy (HBOT) is breathing 100% oxygen inside a chamber pressurized to 1.5 to 3.0 atmospheres absolute (ATA), which raises the oxygen dissolved in blood plasma 10 to 15 times above breathing room air at sea level [1]. It is an established hospital treatment for a defined list of conditions, including decompression sickness, carbon monoxide poisoning and diabetic foot ulcers, while uses such as brain injury, long COVID and longevity remain investigational and are usually paid out of pocket.

Hyperbaric oxygen therapy is one of the oldest and most studied treatments in regenerative medicine, yet most people have never heard of it outside of scuba diving accidents. The concept is simple: you sit or lie inside a pressurized chamber and breathe pure oxygen. The increased pressure forces significantly more oxygen into your blood, your tissues, and your cells than normal breathing ever could.

That extra oxygen triggers a cascade of biological responses: new blood vessel growth, reduced inflammation, stem cell release, and accelerated tissue repair. These effects have made HBOT a standard treatment for certain wound-healing conditions for decades. More recently, researchers have been investigating whether those same mechanisms can help with traumatic brain injuries, stroke recovery, long COVID, and even aging itself.

The sections below cover how HBOT works at the cellular level, what the research shows for approved and off-label uses, the different types of chambers, what a treatment protocol looks like, and the safety, cost and insurance questions to settle before starting. The short version: the evidence is strong for a small number of hospital indications and still early for most of the conditions people search for.

What Is Hyperbaric Oxygen Therapy?

Hyperbaric oxygen therapy is a medical treatment in which a patient breathes close to 100% oxygen while the surrounding pressure is raised above sea level pressure, usually to 2.0 to 3.0 ATA in a hospital chamber. Clinicians also call it hyperbaric oxygen (HBO), HBO2 therapy or hyperbaric medicine, and consumers often search for it as oxygen chamber therapy or a hyperbaric chamber session.

Two conditions have to be met for a treatment to count as HBOT. The patient breathes near pure oxygen, and the chamber pressure is at least 1.4 ATA, which is the threshold the UHMS uses in its definition. Breathing oxygen through a mask at normal pressure is normobaric oxygen therapy, and pressurizing a chamber with room air alone is not HBOT either.

HBOT sits within the wider field of undersea and hyperbaric medicine, a recognized medical subspecialty in the United States. Treatment is prescribed and supervised by a physician, usually in a hospital wound care center or a freestanding hyperbaric clinic, and the chambers themselves are regulated by the US Food and Drug Administration (FDA) as medical devices. You can read how HBOT compares with related options in our hyperbaric oxygen therapy treatment guide.

How Hyperbaric Oxygen Therapy Works

Under normal conditions, you breathe air that contains about 21% oxygen at 1 atmosphere of pressure (sea level). Your red blood cells carry most of that oxygen to your tissues, but hemoglobin can only bind so much. Under normal conditions, hemoglobin is already about 97% saturated with oxygen.

HBOT changes the equation by increasing pressure. According to Henry’s Law, the amount of gas dissolved in a liquid is proportional to the pressure of that gas above the liquid. When you breathe 100% oxygen at 2.0 to 3.0 ATA, the amount of oxygen dissolved directly in your blood plasma increases by 10 to 15 times compared to breathing room air at sea level [1]. This dissolved oxygen reaches tissues that red blood cells cannot easily access, including areas with compromised blood flow.

The Key Biological Mechanisms

Hyperoxygenation. The most immediate effect. Dramatically increased dissolved oxygen in plasma means tissues receive oxygen independent of hemoglobin delivery. This is particularly important in damaged or ischemic tissues where blood vessels are compromised and red blood cells cannot reach [2].

Angiogenesis (new blood vessel growth). Repeated HBOT sessions stimulate the growth of new capillaries in oxygen-starved tissues. This process, driven by vascular endothelial growth factor (VEGF) and other signaling molecules, creates lasting improvements in blood supply to damaged areas. Thom and colleagues (2006) measured an 8-fold increase in circulating stem/progenitor cells involved in blood vessel formation after a course of HBOT [3].

Reduced inflammation. HBOT suppresses inflammatory cytokines and reduces the activity of pro-inflammatory pathways. It also inhibits leukocyte adhesion to damaged blood vessel walls, which is one of the early steps in the inflammatory cascade. This anti-inflammatory effect is relevant to conditions ranging from traumatic brain injury to autoimmune disorders [4].

Stem cell mobilization. A single HBOT session can double the number of circulating stem cells. A full protocol of 20 sessions has been shown to increase circulating CD34+ stem/progenitor cells by up to 800%. These mobilized stem cells home in on areas of damage and contribute to tissue repair [3].

Antimicrobial effects. High oxygen concentrations are directly toxic to anaerobic bacteria (organisms that cannot survive in oxygen-rich environments). HBOT also enhances the ability of white blood cells to kill bacteria through a process called the oxidative burst, and it improves the effectiveness of certain antibiotics [5].

Reduction of edema. HBOT causes vasoconstriction (narrowing of blood vessels) without reducing oxygen delivery, because the increased dissolved oxygen compensates for reduced blood flow. This vasoconstriction reduces swelling in injured tissues, which is why it is used for crush injuries and compartment syndromes [1].

Why Repeated Sessions Matter

Hyperoxygenation ends within minutes of leaving the chamber, so a single session mainly helps acute problems such as carbon monoxide poisoning or a gas bubble in the blood. The slower effects, new capillary growth and stem cell mobilization, build over a series of sessions. That is why wound and radiation injury protocols run for weeks rather than days, and why the number of sessions is one of the first things to ask about when comparing treatment plans [2] [3].

FDA-Approved Uses for HBOT

The FDA clears hyperbaric chambers as medical devices rather than approving the therapy itself. As of July 2021, the FDA consumer update on hyperbaric oxygen therapy listed 13 disorders for which chambers are cleared, and the agency states that it has not cleared any HBOT device for conditions beyond that list. For these indications there is substantial clinical evidence, and insurance typically covers treatment when the patient meets the clinical criteria.

Hospitals and insurers also work from the indications list maintained by the Undersea and Hyperbaric Medical Society (UHMS), which names 14 conditions. The two lists overlap almost entirely, which is why people often refer to the 14 approved uses of HBOT.

The 14 Recognized Indications

1. Decompression sickness (the bends) from scuba diving
2. Air or gas embolism
3. Carbon monoxide poisoning
4. Gas gangrene (clostridial myonecrosis)
5. Crush injuries and acute traumatic ischemia
6. Diabetic foot ulcers and other non-healing wounds
7. Severe anemia (exceptional blood loss when transfusion is not possible)
8. Intracranial abscess
9. Necrotizing soft tissue infections (flesh-eating bacteria)
10. Refractory osteomyelitis (chronic bone infection)
11. Delayed radiation injury (soft tissue and bone necrosis from radiation therapy)
12. Compromised skin grafts and flaps
13. Acute thermal burn injury
14. Idiopathic sudden sensorineural hearing loss

The FDA list also names sudden, painless vision loss in one eye caused by blocked blood flow, which clinicians call central retinal artery occlusion. Severe burns on the FDA list are those treated at a specialized burn center; you can read more about burn care in our burns treatment guide.

Of these, diabetic foot ulcers and delayed radiation injury are the most common reasons people receive HBOT in clinical practice. A Cochrane review by Kranke and colleagues (2015) pooled 12 trials with 577 participants and found that adding HBOT to standard wound care raised the rate of diabetic foot ulcer healing at six weeks (risk ratio 2.35) [6]. The same review found that the benefit was not evident at one year, that the reduction in major amputations did not reach statistical significance, and that design flaws in the trials limited confidence in the results.

For radiation injury, HBOT is often prescribed to patients who develop tissue damage months or years after cancer radiation treatment. The therapy stimulates new blood vessel growth in radiation-damaged tissues, restoring blood supply that radiation destroyed. This is one of the strongest evidence bases for HBOT: a Cochrane review by Bennett and colleagues (2016) found improved outcomes in radiation proctitis, osteoradionecrosis of the jaw and other late radiation injuries [7].

Emergency Uses: Carbon Monoxide Poisoning and Decompression Sickness

Carbon monoxide poisoning and decompression sickness are treated as emergencies, usually at 2.5 to 3.0 ATA and often in only 1 to 3 sessions. In a randomized trial published in the New England Journal of Medicine, Weaver and colleagues (2002) found that three HBOT sessions within 24 hours of acute carbon monoxide poisoning lowered the rate of cognitive problems at six weeks compared with normal-pressure oxygen (Weaver et al., NEJM 2002). Our carbon monoxide poisoning treatment guide covers the emergency pathway in more detail.

For divers with decompression sickness or arterial gas embolism, pressure shrinks the gas bubbles and oxygen speeds the removal of nitrogen. These uses are handled by hospital chambers with 24 hour staffing rather than by wellness clinics.

Off-Label and Investigational Uses

Beyond the 14 recognized conditions, there is a growing body of research exploring HBOT for a range of other conditions. The evidence varies widely, from promising randomized controlled trials to preliminary case series. Off-label HBOT is legal when a physician prescribes it, but it is not covered by insurance and the FDA has not cleared chambers for these uses.

Traumatic Brain Injury (TBI)

This is one of the most actively researched off-label applications. The theory is straightforward: traumatic brain injury causes areas of the brain to become oxygen-starved and inflamed. HBOT delivers oxygen to these damaged regions, reduces neuroinflammation, and stimulates neuroplasticity.

A 2012 phase I study by Harch and colleagues reported that 40 sessions of HBOT at 1.5 ATA were followed by improvements in post-concussion symptoms, cognitive function, and quality of life in military veterans with blast-induced mild TBI. SPECT brain imaging showed increased blood flow to previously hypoperfused brain regions [8]. The study had no control group. A retrospective analysis by Hadanny and colleagues (2018), from the Israeli group affiliated with Tel Aviv University, reported cognitive improvements in patients with chronic TBI, even years after the initial injury [9].

Sham-controlled trials have been less consistent. In the HOPPS trial sponsored by the US Department of Defense (Miller and colleagues, JAMA Internal Medicine, 2015), service members with persistent post-concussion symptoms improved about as much in the sham chamber as in the HBOT chamber. Larger, well-controlled trials are still needed, and the optimal protocol (pressure, number of sessions, timing after injury) remains debated. Our TBI treatment guide sets HBOT alongside the standard rehabilitation options.

Stroke Recovery

Research from Efrati and colleagues at Tel Aviv University has shown that HBOT can reactivate dormant neurons in the penumbra zone, the area surrounding the core stroke damage where cells are alive but not functioning. In a randomized controlled trial, stroke patients who received 40 sessions of HBOT (2.0 ATA, 90 minutes) showed significant neurological improvements compared to a control group, even when treatment started 6 to 36 months after the stroke [10].

The concept of neuroplasticity induced by HBOT in chronic stroke patients challenges the traditional belief that recovery plateaus within the first few months. Results are not consistent across all studies, and more research is needed to identify which patients benefit most.

Long COVID

Several clinical trials have examined HBOT for persistent post-COVID symptoms. A randomized, double-blind, sham-controlled trial from Israel by Zilberman-Itskovich and colleagues (published in Scientific Reports, 2022) showed that 40 sessions of HBOT improved cognitive function, fatigue, sleep, and pain in long COVID patients, with corresponding changes on brain MRI [11].

The proposed mechanisms include reducing neuroinflammation, repairing damaged microvasculature, and restoring mitochondrial function. While these results are promising, long COVID is a heterogeneous condition, and HBOT may work better for certain symptom profiles than others. The FDA has not cleared any HBOT device for COVID-19 or its aftereffects.

Anti-Aging and Longevity

A 2020 study by Hachmo and colleagues, also from Tel Aviv, reported that a specific HBOT protocol (60 daily sessions at 2.0 ATA with intermittent oxygen fluctuations) increased telomere length by more than 20% and decreased senescent cell populations by up to 37% in aging adults [12]. These are two of the key hallmarks of biological aging.

This study received significant attention because telomere lengthening is extremely difficult to achieve with any intervention. It was a small study (35 participants) without a separate control group, and it remains unclear whether these cellular changes translate to meaningful clinical outcomes like reduced disease risk or increased lifespan. Replication studies are ongoing.

Autism Spectrum Disorder

Several small studies have explored HBOT for children with autism, typically using lower pressures (1.3 to 1.5 ATA). A multicenter randomized trial by Rossignol and colleagues (2009) found modest improvements in overall functioning, receptive language, and social interaction in children who received HBOT compared to controls [13]. Later sham-controlled trials did not find a significant benefit, and HBOT is not considered a standard autism treatment. The FDA has specifically warned families that claims about HBOT for autism are not supported by evidence. Families pursuing this option should do so with realistic expectations and under medical supervision.

Lyme Disease

HBOT has been used as an adjunctive treatment for chronic Lyme disease, based on the reasoning that increased oxygen levels can inhibit the Borrelia bacteria and reduce inflammation. The Borrelia organism is microaerophilic (it prefers low-oxygen environments), so hyperbaric oxygen may create an inhospitable environment for it [14]. That reasoning rests on laboratory work with bacteria in culture. Clinical evidence is limited to case reports and small series, no large randomized trials have been conducted, and the FDA lists Lyme disease among the claims for HBOT it considers unsupported. Patients who pursue HBOT for Lyme typically do so as part of a multi-modal treatment approach.

Fibromyalgia and Other Conditions

Small trials have also looked at HBOT for fibromyalgia, chronic fatigue syndrome, post-concussion syndrome and post-traumatic stress, many of them from the same Israeli research group led by Shai Efrati. These studies are early, mostly small, and rarely sham controlled, so they are best read as reasons for further research rather than as evidence of benefit.

Types of Hyperbaric Chambers

Hyperbaric chambers differ in ways that change the treatment itself. The type of chamber determines the maximum pressure achievable, the oxygen concentration delivered, and the overall treatment experience.

Hard-Shell Monoplace Chambers

These are the clinical standard. A monoplace chamber is a clear acrylic tube designed for one person. The entire chamber is pressurized with 100% oxygen, so you simply breathe the chamber atmosphere. Maximum pressures typically reach 3.0 ATA, covering the full range of clinical protocols.

Monoplace chambers are found in hospitals and dedicated hyperbaric clinics. They offer the highest pressures and are required for all FDA-approved indications. The downside is cost (sessions typically run $250 to $400) and the fact that you must travel to a clinic for each session.

Hard-Shell Multiplace Chambers

Multiplace chambers are large enough for several patients (and sometimes a medical attendant) to sit inside simultaneously. The chamber is pressurized with air, and patients breathe 100% oxygen through individual masks or hoods. These are typically found in hospital-based hyperbaric programs and military facilities.

Multiplace chambers can reach the same pressures as monoplace chambers and have the advantage of allowing a medical professional to be inside the chamber with the patient. This is particularly useful for critically ill patients or those who need hands-on monitoring during treatment.

Soft-Shell (Mild) Chambers

Soft-shell or “mild” hyperbaric chambers are portable, inflatable units designed for home use. They typically reach a maximum pressure of 1.3 to 1.5 ATA and use an oxygen concentrator (delivering approximately 24 to 40% oxygen) rather than 100% pure oxygen.

There is an important distinction here. Soft-shell chambers operating at 1.3 ATA with concentrated oxygen do not deliver the same physiological stimulus as a clinical chamber at 2.0 to 3.0 ATA with 100% oxygen. The total dissolved oxygen achieved is significantly lower. Whether this lower dose produces meaningful clinical benefits is debated. Some research suggests that even mild pressures (1.3 ATA) can produce measurable biological effects [13], while critics argue the dose is too low for most therapeutic applications.

The regulatory picture matters too. According to the FDA, zippered soft chambers are cleared only to treat altitude sickness, and the agency has not cleared them for use with oxygen tanks or oxygen concentrators. Adding oxygen to a soft chamber at home carries a fire risk the FDA has warned about. Our comparison of mild HBOT and clinical HBOT goes deeper on the trade-offs.

Soft-shell chambers cost $5,000 to $20,000 to purchase and can be used at home without clinical supervision. For people who want regular sessions over months or years, the economics can favor purchasing a home unit, even with the limitations in pressure and oxygen concentration.

What a Treatment Protocol Looks Like

HBOT is not a one-session treatment. Nearly all protocols involve a series of sessions, and the specific parameters vary depending on what condition is being treated.

Pressure Settings

• 1.3 to 1.5 ATA: Considered “mild” HBOT. Used in soft-shell home chambers and some TBI/concussion protocols
• 1.5 to 2.0 ATA: Moderate range. Common for off-label neurological applications, wound healing support, and general wellness
• 2.0 to 2.5 ATA: Standard clinical range. Used for most FDA-approved indications, including diabetic wounds and radiation injury
• 2.5 to 3.0 ATA: High-pressure protocols. Reserved for acute conditions like carbon monoxide poisoning, gas embolism, and decompression sickness

Session Duration and Frequency

A typical HBOT session lasts 60 to 90 minutes at treatment pressure, with additional time for pressurization (5 to 10 minutes) and depressurization (5 to 10 minutes). Most protocols call for sessions five days per week, with weekends off.

The total number of sessions depends on the condition:

• Acute conditions (decompression sickness, CO poisoning): 1 to 10 sessions
• Wound healing: 20 to 40 sessions
• Radiation injury: 30 to 60 sessions
• TBI/neurological: 40 to 60 sessions
• General wellness/anti-aging: 40 to 60 sessions (based on the telomere study protocol)

A full protocol typically spans 4 to 12 weeks, depending on the session frequency and total number of treatments prescribed.

What to Expect During a Session

Before your first session, you will have a medical evaluation and be screened for contraindications. You will need to wear cotton clothing (no synthetic fabrics, as they can generate static electricity in an oxygen-rich environment). Electronics, lighters, and petroleum-based products are not allowed in the chamber.

During pressurization, you will feel pressure in your ears, similar to the sensation during airplane descent. You can equalize by swallowing, yawning, or performing the Valsalva maneuver (gently blowing with your nose pinched). Once at treatment pressure, most people simply rest, read, or sleep for the duration of the session. The chamber is typically clear, so claustrophobia is manageable for most people, though some facilities offer chambers with entertainment systems.

After the session, you may feel slightly lightheaded or fatigued. Some people report increased energy. These effects are usually mild and short-lived.

How to Prepare for Your First Session

1. Bring a full medication list. Some chemotherapy drugs and other medicines interact with high-pressure oxygen, and the hyperbaric physician needs to see them before you start.
2. Report a cold, sinus congestion or allergies. Blocked ears and sinuses are the main cause of pressure pain, and a short delay is usually better than forcing equalization.
3. Eat a normal meal if you have diabetes. HBOT can lower blood sugar in people who use insulin, so clinics usually check glucose before and after each session.
4. Leave cosmetics, hair products and lotions at home. Petroleum and alcohol-based products are fire hazards in an oxygen-rich chamber.
5. Ask how the team will track progress. Wound photographs, symptom scores or cognitive tests at set points show whether the course is helping.

HBOT Compared With Other Oxygen Treatments

Hyperbaric oxygen therapy is often confused with other treatments that also involve oxygen. The defining difference is pressure: only HBOT raises the pressure enough to push large amounts of oxygen into plasma, and that is what drives the effects described above.

• Normobaric oxygen therapy delivers extra oxygen through a mask or nasal cannula at normal pressure. It is standard care for COPD and other lung disease but does not reach the plasma oxygen levels of HBOT. See our oxygen therapy guide for the medical uses.
• Exercise with oxygen therapy (EWOT) combines exercise with breathing concentrated oxygen at normal pressure. It is a wellness practice with limited research behind it.
• Ozone therapy uses a mixture of oxygen and ozone gas, usually given through the blood or by injection. It is a different treatment with a different evidence base, covered in our ozone therapy guide.
• Red light therapy and NAD+ IV therapy are sometimes offered alongside HBOT in longevity clinics. They work through unrelated mechanisms and have their own, generally thinner, evidence.

Among these options, HBOT has the strongest evidence for wound healing and for acute gas bubble and carbon monoxide problems, because those uses have been studied in hospital settings for decades.

Risks and Side Effects

HBOT has a strong overall safety profile when administered by trained professionals following established protocols. According to the FDA, serious complications are rare when chambers are used for cleared indications. There are still known risks to understand before starting.

Common Side Effects

• Ear barotrauma: The most common side effect. Pressure changes can cause ear pain, a feeling of fullness, or, in rare cases, eardrum perforation. Proper equalization techniques prevent most ear issues. Patients with upper respiratory infections or allergies may need to postpone treatment if they cannot equalize effectively.
• Sinus pain: Similar to ear barotrauma, sinus cavities can be affected by pressure changes. This is more common in patients with sinus congestion.
• Temporary myopia (nearsightedness): Prolonged exposure to high-pressure oxygen can cause temporary changes in the shape of the eye lens, resulting in nearsightedness. This typically resolves within weeks to months after completing a treatment course [15].
• Low blood sugar: People with diabetes who use insulin can see glucose fall during treatment, which is why many clinics check it around each session.
• Claustrophobia and fatigue: Some people feel anxious in a monoplace chamber or tired after sessions. Both are usually manageable and short-lived.

Rare but Serious Risks

• Oxygen toxicity seizures: At pressures above 2.0 ATA, there is a small risk of central nervous system oxygen toxicity, which can cause seizures. Hampson and Atik (2003) reviewed 20,328 routine treatments and recorded 6 oxygen toxicity seizures, an incidence of 1 in 3,388 treatments (0.03%). The risk increases with higher pressures and longer exposure times [16].
• Pulmonary oxygen toxicity: Prolonged exposure to high-concentration oxygen can cause lung irritation. Clinical protocols are designed to stay within safe exposure limits.
• Lung collapse: The FDA lists collapsed lung (pneumothorax) as a rare complication, which is why chest problems are screened before treatment.
• Fire risk: Oxygen-enriched environments are fire hazards. This is why strict safety protocols prohibit certain items inside the chamber. Chamber fires are rare, but they can be fatal: a five-year-old boy died in a chamber fire at a Michigan clinic in January 2025. Our account of how hyperbaric chamber fires happen explains the safety checks to look for.

Contraindications

HBOT is contraindicated in patients with untreated pneumothorax (collapsed lung). Relative contraindications include certain types of seizure disorders, severe COPD, active upper respiratory infections, and some ear/sinus conditions. Patients taking certain medications (particularly bleomycin and cisplatin) should discuss potential interactions with their hyperbaric physician.

Doxorubicin, disulfiram and the burn cream mafenide acetate are other drugs hyperbaric physicians ask about. Pregnancy, a recent ear or chest operation and implanted devices that are not rated for pressure also call for a specialist review before the first session. A fuller list is in our article on hyperbaric chamber side effects.

Cost and Insurance

The cost of HBOT varies by location, type of facility, and the specific protocol prescribed.

Per-Session Costs

• Hospital-based programs: $300 to $500 per session (sometimes higher)
• Freestanding hyperbaric clinics: $200 to $350 per session
• Soft-shell home chambers (purchase): $5,000 to $20,000 upfront, minimal per-session cost after purchase

Full Protocol Costs

With 20 to 40 sessions being standard, a full treatment course at a clinic typically runs $4,000 to $16,000 out of pocket. For conditions requiring 40 to 60 sessions, costs can reach $12,000 to $24,000.

Insurance Coverage

Insurance (including Medicare) covers HBOT for FDA-approved indications when provided by an approved facility with a physician’s prescription. Coverage typically requires documentation showing that the condition meets specific clinical criteria and that the patient has failed other standard treatments.

Medicare spells out its rules in National Coverage Determination 20.29. For diabetic wounds of the lower legs, the wound must be Wagner grade III or higher and show no measurable healing after at least 30 days of standard wound care, and treatment stops being covered if a 30 day period passes without measurable progress. The same document lists conditions Medicare will not pay for, including multiple sclerosis, arthritic diseases and senility.

For off-label uses (TBI, anti-aging, long COVID, etc.), insurance does not cover the cost. Some patients have successfully appealed insurance denials for conditions with strong emerging evidence, but this is not common. Most people pursuing off-label HBOT pay out of pocket.

What the Research Shows: A Balanced View

The research on HBOT spans a wide spectrum. For FDA-approved indications, the evidence is strong and well-established. For off-label uses, the picture is more nuanced.

Strong evidence: Diabetic foot ulcers, radiation injury, decompression sickness, carbon monoxide poisoning. These are backed by decades of clinical data, including randomized controlled trials and systematic reviews [6][7].

Promising evidence: Traumatic brain injury, stroke recovery, long COVID, anti-aging markers (telomere length, senescent cells). These have positive results from controlled trials, but sample sizes are still relatively small and replication is ongoing [8][9][10][11][12].

Preliminary evidence: Autism, Lyme disease, fibromyalgia, chronic fatigue syndrome. These have limited clinical data, mostly case series or small pilot studies. Larger trials are needed before drawing firm conclusions [13][14].

One important challenge in HBOT research is the difficulty of creating a convincing placebo. Patients typically know whether the chamber is pressurized, which makes true double-blinding difficult. Some studies use a sham condition with lower pressure or room air, but whether participants can tell the difference remains a concern [17].

Who Provides Hyperbaric Oxygen Therapy?

HBOT in the United States is prescribed by a physician and delivered by a trained hyperbaric team. In hospitals, that physician is often board certified in undersea and hyperbaric medicine, a subspecialty certified through the American Board of Preventive Medicine and the American Board of Emergency Medicine. Wound care specialists, emergency physicians and plastic surgeons also refer patients and oversee care.

The people running the chamber are usually certified hyperbaric technologists (CHT) or certified hyperbaric registered nurses (CHRN), credentials issued by the National Board of Diving and Hyperbaric Medical Technology. Freestanding clinics that offer off-label HBOT vary more in staffing, so asking who is on site during each session is worthwhile.

How to Find a Provider

If you are considering HBOT, here are practical steps for finding a qualified provider:

1. For FDA-approved indications: Start with your primary care physician or specialist. They can refer you to a hospital-based hyperbaric program. The Undersea and Hyperbaric Medical Society (UHMS) maintains a directory of accredited hyperbaric facilities at uhms.org.
2. For off-label uses: Look for a clinic with a physician who is board-certified in hyperbaric medicine (either through the American Board of Preventive Medicine or the American Board of Emergency Medicine). Avoid facilities that do not have a physician overseeing treatment protocols.
3. Questions to ask: What type of chamber do they use? What pressure and oxygen concentration? How many sessions do they recommend for your condition, and what outcomes do they typically see? What is their safety record?

To compare options near you, start with the directory of hyperbaric oxygen therapy clinics and filter by state or city. Regenerated.com is free for patients. The order of the list is not a paid ranking, Featured slots are clearly labeled and capped, and Verified means the clinic completed our credential checks rather than paying for placement. Inclusion in the directory is not an endorsement, and our guide to Featured, Verified and organic listings explains each label.

Use each listing to check the chamber type, the supervising physician and whether the clinic treats listed indications, off-label conditions or both. A clinic that is clear about pressure, oxygen concentration and the evidence for your condition is easier to evaluate than one that leads with testimonials.

The Bottom Line

Hyperbaric oxygen therapy works by pushing more oxygen into your tissues than normal breathing allows, triggering a cascade of healing responses: new blood vessel growth, reduced inflammation, stem cell mobilization, and enhanced tissue repair. For its FDA-approved indications, the evidence is solid and insurance typically covers treatment. For emerging applications like TBI, stroke recovery, long COVID, and anti-aging, the science is genuinely promising but still evolving.

If you are considering HBOT, your first step is identifying whether your condition falls within the FDA-approved list (which simplifies insurance coverage) or whether you would be pursuing off-label treatment (which means paying out of pocket). Either way, work with a board-certified hyperbaric physician who can design a protocol specific to your situation, monitor your progress, and adjust treatment as needed.

Related Reading

• Ozone Therapy: The Complete Guide
• NAD+ IV Therapy: The Complete Guide
• Anti-Aging Supplements Guide
• Red Light Therapy Guide

Frequently Asked Questions

Does hyperbaric oxygen therapy actually work?

Hyperbaric oxygen therapy works well for its recognized indications, such as carbon monoxide poisoning, decompression sickness, delayed radiation injury and selected diabetic foot ulcers, where randomized trials and Cochrane reviews support its use. For off-label uses like brain injury, stroke and long COVID, controlled trials show promising results, but samples are small, some sham-controlled trials found no difference, and replication is ongoing, so those benefits are not yet established.

What conditions is HBOT approved and used for?

The FDA has cleared hyperbaric chambers for 13 disorders, and the UHMS lists 14 indications. They include decompression sickness, gas embolism, carbon monoxide poisoning, gas gangrene, crush injury, diabetic foot ulcers, delayed radiation injury, compromised skin grafts, severe anemia, severe burns, serious bone and soft tissue infections and sudden hearing loss. In practice, diabetic foot ulcers and delayed radiation injury are the most common reasons people receive HBOT.

How much does hyperbaric oxygen therapy cost?

Hyperbaric oxygen therapy costs about $300 to $500 per session at hospitals and $200 to $350 at freestanding clinics. A standard course of 20 to 40 sessions typically costs $4,000 to $16,000, and longer off-label protocols of 40 to 60 sessions can reach $12,000 to $24,000. Medicare and private insurers cover listed indications that meet their criteria, while most people pay out of pocket for off-label uses.

Is HBOT safe, and what are the side effects?

HBOT is generally safe when a trained team follows established protocols, and serious complications are rare. Ear barotrauma is the most common side effect, followed by sinus pain and temporary nearsightedness that usually resolves within weeks to months. Oxygen toxicity seizures occurred in about 1 in 3,388 routine treatments in one large hospital series. Untreated pneumothorax rules treatment out, and severe COPD or certain medications require caution.

How many sessions does HBOT take and how long is each one?

Each HBOT session lasts 60 to 90 minutes at treatment pressure, plus 5 to 10 minutes each to pressurize and depressurize, usually five days per week. Acute conditions such as carbon monoxide poisoning may need 1 to 10 sessions, wound healing 20 to 40, radiation injury 30 to 60, and neurological or wellness uses 40 to 60. A typical protocol spans 4 to 12 weeks.

What is the difference between hard-shell and soft-shell chambers?

Hard-shell clinical chambers reach up to 3.0 ATA and deliver 100% oxygen, and they are required for all FDA-cleared indications. Soft-shell mild chambers reach only 1.3 to 1.5 ATA using a concentrator at about 24 to 40% oxygen, so they deliver far less dissolved oxygen. The FDA has cleared soft chambers only for altitude sickness. For serious conditions, you almost certainly need clinical-grade HBOT.

Sources

1. Gill AL, Bell CN. Hyperbaric oxygen: its uses, mechanisms of action and outcomes. QJM. 2004;97(7):385-395. doi:10.1093/qjmed/hch074 ↩
2. Thom SR. Hyperbaric oxygen: its mechanisms and efficacy. Plast Reconstr Surg. 2011;127(Suppl 1):131S-141S. doi:10.1097/PRS.0b013e3181fbe2bf ↩
3. Thom SR, Bhopale VM, Velazquez OC, Goldstein LJ, Thom LH, Buerk DG. Stem cell mobilization by hyperbaric oxygen. Am J Physiol Heart Circ Physiol. 2006;290(4):H1378-H1386. doi:10.1152/ajpheart.00888.2005 ↩
4. Benson RM, Minter LM, Osborne BA, Granowitz EV. Hyperbaric oxygen inhibits stimulus-induced proinflammatory cytokine synthesis by human blood-derived monocyte-macrophages. Clin Exp Immunol. 2003;134(1):57-62. doi:10.1046/j.1365-2249.2003.02248.x ↩
5. Memar MY, Yekani M, Alizadeh N, Baghi HB. Hyperbaric oxygen therapy: antimicrobial mechanisms and clinical application for infections. Biomed Pharmacother. 2019;109:440-447. doi:10.1016/j.biopha.2018.10.142 ↩
6. Kranke P, Bennett MH, Martyn-St James M, Schnabel A, Debus SE, Weibel S. Hyperbaric oxygen therapy for chronic wounds. Cochrane Database Syst Rev. 2015;(6):CD004123. doi:10.1002/14651858.CD004123.pub4 ↩
7. Bennett MH, Feldmeier J, Hampson NB, Smee R, Milross C. Hyperbaric oxygen therapy for late radiation tissue injury. Cochrane Database Syst Rev. 2016;4(4):CD005005. doi:10.1002/14651858.CD005005.pub4 ↩
8. Harch PG, Andrews SR, Fogarty EF, et al. A phase I study of low-pressure hyperbaric oxygen therapy for blast-induced post-concussion syndrome and post-traumatic stress disorder. J Neurotrauma. 2012;29(1):168-185. doi:10.1089/neu.2011.1895 ↩
9. Hadanny A, Abbott S, Engelman G, et al. Effect of hyperbaric oxygen therapy on chronic neurocognitive deficits of post-traumatic brain injury patients: retrospective analysis. BMJ Open. 2018;8(9):e023387. doi:10.1136/bmjopen-2018-023387 ↩
10. Efrati S, Fishlev G, Bechor Y, et al. Hyperbaric oxygen induces late neuroplasticity in post stroke patients: randomized, prospective trial. PLoS One. 2013;8(1):e53716. doi:10.1371/journal.pone.0053716 ↩
11. Zilberman-Itskovich S, Catalogna M, Sasson E, et al. Hyperbaric oxygen therapy improves neurocognitive functions and symptoms of post-COVID condition: randomized controlled trial. Sci Rep. 2022;12(1):11252. doi:10.1038/s41598-022-15565-0 ↩
12. Hachmo Y, Hadanny A, Abu Hamed R, et al. Hyperbaric oxygen therapy increases telomere length and decreases immunosenescence in isolated blood cells: a prospective trial. Aging (Albany NY). 2020;12(22):22445-22456. doi:10.18632/aging.202188 ↩
13. Rossignol DA, Rossignol LW, Smith S, et al. Hyperbaric treatment for children with autism: a multicenter, randomized, double-blind, controlled trial. BMC Pediatr. 2009;9:21. doi:10.1186/1471-2431-9-21 ↩
14. Huang CY, Chen JH, Tsai YF, Hsieh YL, Shi GY, Wu HL. In vitro effects of hyperbaric oxygen on aggressive Borrelia burgdorferi. J Microbiol Immunol Infect. 2014;47(4):271-276. doi:10.1016/j.jmii.2012.11.006 ↩
15. Evanger K, Vaagbo G, Haugen OH, Borsheim E. Myopic shift during hyperbaric oxygen therapy. Acta Ophthalmol. 2011;89(8):714-717. doi:10.1111/j.1755-3768.2009.01830.x ↩
16. Hampson N, Atik D. Central nervous system oxygen toxicity during routine hyperbaric oxygen therapy. Undersea Hyperb Med. 2003;30(2):147-153. PMID: 12964858 ↩
17. Lansdorp CA, van Hulst RA. Double-blind trials in hyperbaric medicine: a narrative review on past experiences and considerations in designing sham hyperbaric treatment. Clin Trials. 2018;15(5):462-476. doi:10.1177/1740774518776952 ↩

About the medical reviewer

Dr. Bronwyn Holmes, MD, FAARFM is a physician specialising in regenerative medicine, advanced peptide therapeutics, exosome and stem cell biology, hormonal health, and longevity. Last reviewed July 5, 2026.