Hyperbaric Oxygen Therapy for TBI and Concussion: What the Evidence Says

Hyperbaric oxygen therapy (HBOT) is not FDA approved for traumatic brain injury (TBI) or concussion, and the research on it is mixed: randomized trials from Dr. Shai Efrati’s group in Israel, such as Boussi-Gross et al. (2013), reported better memory, attention and brain perfusion after 40 sessions at 1.5 ATA, while US Department of Defense sham-controlled trials, including HOPPS (Miller et al., 2015), found that people in the sham chamber improved about as much as those breathing oxygen. HBOT for persistent post-concussion symptoms is an off-label, usually cash pay option that belongs alongside standard brain injury rehabilitation, not in place of it.

At a Glance

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Traumatic brain injury affects an estimated 2.8 million Americans every year, according to Centers for Disease Control and Prevention (CDC) estimates of TBI-related emergency visits, hospital stays and deaths. For many of them, especially people with persistent post-concussive symptoms or chronic TBI, standard treatment options feel frustratingly limited. Rest, cognitive rehabilitation and medication management help, but they do not always resolve the lingering brain fog, headaches, mood disturbances and cognitive deficits that can persist for months or years after injury.

Hyperbaric oxygen therapy (HBOT) has become one of the most actively researched complementary treatments for TBI and concussion. The premise is simple: deliver more oxygen to a brain that is struggling to heal. The evidence has not reached the level required for FDA approval, yet many neurologists, physiatrists, functional medicine practitioners and military researchers now consider HBOT a reasonable option to discuss with selected patients.

Hyperbaric oxygen therapy is also written as HBOT, HBO2 or hyperbaric oxygenation. In brain injury research it is studied mostly for mild traumatic brain injury (mTBI), post-concussion syndrome (PCS, also called persistent post-concussive symptoms) and blast-related injury with overlapping post-traumatic stress disorder (PTSD). The sections below cover how it works, what each major study found, the usual protocol, risks, costs and how to choose a provider.

How HBOT Affects the Injured Brain

HBOT may help TBI because it changes how much oxygen reaches brain tissue that has lost part of its blood supply. To see why that matters, it helps to know what happens in the brain after a concussion or a more severe traumatic injury.

The Problem: What TBI Does to the Brain

A traumatic brain injury triggers a cascade of damaging processes:

• Neuroinflammation: The brain’s immune cells (microglia) become chronically activated, creating ongoing inflammation that damages healthy tissue.
• Impaired blood flow: Tiny blood vessels in the brain are damaged, reducing oxygen delivery to areas that need it most.
• Metabolic crisis: Injured neurons require more energy to function but receive less, creating an energy deficit that impairs healing.
• Reduced neuroplasticity: The brain’s ability to form new connections and repair existing ones is compromised.

These processes can persist for months or years after the initial injury, which is why many TBI patients experience chronic symptoms long after the “expected” recovery window.

The Solution: How HBOT Addresses Each Mechanism

HBOT targets each of these processes through a single intervention: it sharply increases the amount of oxygen dissolved in the blood plasma and, from there, in brain tissue.

• Anti-inflammatory effect: In animal and laboratory studies, hyperbaric oxygen suppresses microglial activation and lowers pro-inflammatory cytokines in brain tissue, quieting the chronic neuroinflammation that drives ongoing damage.
• Angiogenesis: Repeated HBOT sessions stimulate the formation of new blood vessels in damaged brain regions, which may restore oxygen delivery to areas that have been chronically under-perfused.
• Metabolic support: By raising dissolved oxygen independent of hemoglobin, HBOT supplies the metabolic fuel that injured neurons need to function and repair.
• Neuroplasticity enhancement: HBOT upregulates brain-derived neurotrophic factor (BDNF) and other growth factors that support the formation of new neural connections, which may help the brain rewire around damaged areas.

Put simply: TBI can leave a brain that is inflamed, under-oxygenated, energy-starved and struggling to adapt, and HBOT acts on each of those problems. That is why the theoretical rationale for HBOT in TBI is strong, and why researchers keep testing whether the rationale holds up in patients.

The Evidence: Key Studies and Findings

The research on HBOT for TBI and concussion falls into two main bodies of work: US military and VA trials, and Israeli trials from the Sagol Center for Hyperbaric Medicine and Research at Shamir Medical Center. The two groups used different control conditions, and that difference explains much of the disagreement in their results.

Military and VA Research

The U.S. military has been at the forefront of HBOT research for TBI, driven by the large number of blast-related brain injuries from Iraq and Afghanistan. Key findings include:

• Harch et al. (2012), a pilot study: An uncontrolled phase I study in military veterans with blast-related persistent post-concussion syndrome reported significant improvements in symptoms, cognitive function, PTSD symptoms and quality of life after 40 sessions of HBOT at 1.5 ATA. SPECT brain imaging showed increased blood flow to previously hypoperfused brain regions. Because it had no control group, it shows feasibility rather than effect size.
• Cifu et al. (2014): A DoD-funded study in Marines with persistent post-concussive symptoms compared HBOT at 2.0 ATA with a pressurized sham and found no meaningful difference between the groups. Critics noted that any sham that pressurizes the chamber is itself a mild hyperbaric exposure, so the study may have compared two doses of pressure rather than HBOT against placebo.
• Wolf et al. (2012): In active-duty Air Force service members with mild TBI, post-concussive symptoms improved in both the HBOT group (2.4 ATA, 30 sessions) and a sham group breathing air at low pressure, with no significant difference between them.
• HOPPS (Miller et al., 2015): The Hyperbaric Oxygen for Persistent Post-concussive Symptoms trial, published in JAMA Internal Medicine, randomized service members to HBOT at 1.5 ATA, a sham chamber or usual care. Both chamber groups improved more than usual care, but HBOT did not outperform the sham.
• BIMA (Weaver et al., 2018): The Brain Injury and Mechanisms of Action trial reported some short-term gains in post-concussive and PTSD symptoms after 40 sessions at 1.5 ATA compared with sham, and those differences had faded by the 12-month follow-up.

Israeli Research (Efrati and Colleagues)

Some of the most cited evidence for HBOT in TBI comes from the research group led by Dr. Shai Efrati at the Shamir Medical Center in Israel:

• Boussi-Gross et al. (2013): A randomized crossover trial in PLoS One in chronic TBI patients (1 to 5 years post-injury) reported significant improvements in cognitive function, including memory, attention and executive function, after 40 sessions at 1.5 ATA. SPECT imaging showed increased brain perfusion in areas that had been damaged.
• Hadanny et al. (2018): Extended findings to patients with chronic post-concussion syndrome, reporting significant improvements in cognitive scores and quality of life measures. Brain imaging again showed measurable increases in cerebral blood flow.
• Efrati et al. (2022): Reported results from a randomized trial showing HBOT-associated neuroplasticity on advanced MRI sequences (DTI and perfusion MRI), offering objective imaging evidence of structural and functional change in the brain alongside symptom improvement.

The Israeli studies stand out because they combine clinical outcome measures with advanced neuroimaging, providing both subjective and objective evidence of benefit. Their main limitation is that most compared HBOT with no treatment or delayed treatment rather than with a sham chamber, so expectation effects are harder to rule out.

Why the Military Trials and the Israeli Trials Disagree

The core dispute is about the control group. The US military trials used sham chambers that were pressurized slightly above sea level while patients breathed air, and in those trials the sham groups often improved about as much as the HBOT groups. One reading is that the improvement was a placebo or attention effect; the other, argued by researchers such as Paul Harch, is that the sham pressure itself had a biological effect.

The Israeli trials mostly used crossover or wait-list designs, which show a clear difference between treated and untreated periods but cannot fully separate HBOT from the effects of daily clinic visits and expectation. Both readings are still debated, and no single trial has settled the question. The protocol differences between these research groups are covered in more detail in the comparison of the Efrati and Harch HBOT protocols.

Evidence Summary Table

The table below summarizes the population, protocol and main finding of each study discussed above, including the control condition where it changes how the result should be read.

Study	Population	Protocol	Key Outcome	Imaging Evidence
Harch et al. (2012)	Veterans with mild TBI / PCS	1.5 ATA, 60 min, 40 sessions, no control group	Significant symptom and cognitive improvement	SPECT: increased perfusion
Boussi-Gross et al. (2013)	Chronic TBI (1 to 5 years post)	1.5 ATA, 60 min, 40 sessions, crossover vs. no treatment	Improved memory, attention, executive function	SPECT: increased perfusion
Wolf et al. (2012)	Active-duty military, mild TBI	2.4 ATA, 60 min, 30 sessions vs. sham	Both groups improved; no significant difference vs. sham	Not included
Hadanny et al. (2018)	Chronic post-concussion syndrome	1.5 ATA, 60 min, 40 sessions	Cognitive and quality-of-life improvements	SPECT: increased blood flow
Efrati et al. (2022)	Chronic TBI patients	2.0 ATA, 90 min, 60 sessions	Neuroplasticity changes and cognitive gains	DTI and perfusion MRI: structural changes
Cifu et al. (2014)	Military, persistent PCS	2.0 ATA vs. pressurized sham, 40 sessions	No meaningful difference vs. sham (sham debate)	Not conclusive
HOPPS, Miller et al. (2015)	Military, persistent post-concussive symptoms	1.5 ATA, 40 sessions vs. sham vs. usual care	Chamber groups beat usual care; HBOT equal to sham	Not a primary outcome
BIMA, Weaver et al. (2018)	Military, persistent post-concussive symptoms	1.5 ATA, 40 sessions vs. sham	Short-term symptom gains, not sustained at 12 months	Exploratory imaging only

Does HBOT Work for Concussion and Post-Concussion Syndrome?

HBOT has not been shown to work for concussion in the way the FDA or major guideline bodies require, and it has produced real improvement for some patients in trials. Most people who receive HBOT for persistent post-concussion syndrome in studies report fewer symptoms afterward. The open question is how much of that change comes from the oxygen and how much comes from pressure, structured daily care and expectation.

For acute concussion, most people recover within weeks with relative rest, a gradual return to activity and symptom-specific care, so HBOT is rarely relevant in the first days. The research and the clinical interest focus on people whose headaches, dizziness, brain fog or mood symptoms last months or years. More on that group is in the overview of post-concussion syndrome symptoms and recovery, and the condition page on traumatic brain injury lists the wider set of treatments people explore.

The HBOT Protocol for TBI

Based on published research, the most commonly used HBOT protocols for TBI include:

• Pressure: 1.5 to 2.0 ATA (atmospheres absolute). Most TBI studies use the lower end of this range (1.5 ATA), which is notable because many other HBOT indications use higher pressures.
• Gas: 100% oxygen delivered via mask or hood inside a pressurized chamber.
• Session duration: 60 to 90 minutes of treatment time at pressure (not counting compression and decompression, which add 10 to 15 minutes each).
• Number of sessions: 40 to 60 sessions, typically delivered 5 days per week over 8 to 12 weeks.
• Some protocols include maintenance sessions after the initial treatment block, with weekly or monthly sessions intended to sustain gains. There is little trial data on maintenance schedules.

Protocols in brain injury research are run in medical-grade chambers that reach 1.5 ATA or higher. Soft-sided “mild” chambers usually operate near 1.3 ATA and are not the equipment used in the TBI trials above; the differences are laid out in mild HBOT vs. clinical HBOT.

Does Timing Matter?

HBOT appears to help both acute and chronic brain injury patients in some studies, though the mechanisms and expectations differ:

• Acute TBI (within days to weeks of injury): HBOT may reduce secondary brain damage by controlling inflammation and supporting metabolic function during the early healing window. Animal studies consistently show reduced lesion size and better neurological outcomes when HBOT is applied early. In people, moderate and severe acute TBI is managed in hospital and trauma care first.
• Chronic TBI (months to years after injury): This is where most human studies have been conducted. The Israeli studies, in particular, suggest that the brain retains some capacity for HBOT-associated repair even years after injury, so “too late” may be later than previously thought.

Earlier intervention may produce better results, although there are no head-to-head human trials of early versus late HBOT. If you are considering HBOT after a concussion or TBI, there is no evidence that delaying a conversation with your care team helps.

What Sessions Feel Like: Patient Experience

If you have never been inside a hyperbaric chamber, here is what to expect:

• The chamber: Clinical HBOT chambers are either monoplace (single person, acrylic tube) or multiplace (room-sized, multiple patients). Both achieve the same therapeutic pressures.
• Compression (5 to 10 minutes): As the chamber pressurizes, you will feel pressure in your ears, similar to descending in an airplane. You clear your ears by yawning, swallowing or using the Valsalva maneuver (gently blowing against pinched nostrils).
• Treatment time (60 to 90 minutes): Once at pressure, you breathe normally, either through a mask or hood delivering 100% oxygen or, in many monoplace chambers, from the oxygen-filled chamber itself. You can rest, listen to audio or simply sleep. Electronics are usually restricted inside the chamber because of fire safety, so ask the clinic what is allowed. Many patients find the sessions relaxing.
• Decompression (5 to 10 minutes): The chamber slowly returns to normal pressure. You may feel mild popping in your ears.

Common Timeline for Improvement

Clinics that treat brain injury often describe a pattern like the one below. It comes from clinical experience and small studies rather than controlled trials, so treat it as a rough guide.

• Sessions 1 to 10: Some patients notice better sleep and fewer headaches. Some experience temporary fatigue or mild symptom fluctuation as the brain responds to increased oxygenation.
• Sessions 10 to 20: Cognitive changes may begin to emerge, such as clearer thinking, better word-finding and improved short-term memory. Family members may notice changes before the patient does.
• Sessions 20 to 40: Some patients report larger improvements in energy, mood and cognitive endurance, and describe feeling “more like themselves” for the first time since their injury.
• Sessions 40 to 60: Consolidation and continued improvement. Some patients report their largest gains in this later phase.

Not every patient follows this timeline, and some notice no meaningful benefit even after the full 60 sessions. Progress, when it comes, is usually gradual rather than dramatic.

Who Should Not Have HBOT? Risks and Contraindications

HBOT is generally well tolerated at the 1.5 to 2.0 ATA pressures used in TBI protocols, and it still carries real risks that a hyperbaric physician screens for before the first session. The screening matters more for brain injury patients, because some have seizure histories, sinus or ear damage, or medications that change their risk.

Common side effects

• Middle ear barotrauma: Ear pressure or pain during compression is the most common problem, and it is usually managed by slowing compression or teaching ear-clearing techniques.
• Sinus pressure: Congestion from a cold or allergies can make sessions uncomfortable, and clinics often postpone a session until it clears.
• Temporary vision change: A mild shift toward nearsightedness can develop over a long course and usually resolves in the weeks after treatment ends.
• Fatigue: Many people feel tired after sessions, especially early in the course.

Rare but serious risks

Central nervous system oxygen toxicity, which can cause a seizure, and lung barotrauma are rare, and the risk is lower at 1.5 ATA than at the higher pressures used for wounds or decompression sickness. Fire is a known chamber hazard, which is why clinics restrict what patients bring inside. More detail is in the guide to hyperbaric chamber side effects.

Who usually should not have HBOT

An untreated pneumothorax (collapsed lung) is the standard absolute contraindication. Hyperbaric physicians also review recent chest or ear surgery, poorly controlled seizures, severe claustrophobia, uncontrolled fever, pregnancy and certain drugs, including some chemotherapy agents such as bleomycin, cisplatin and doxorubicin, and disulfiram. A seizure history after brain injury does not automatically rule HBOT out, but it should be discussed openly with the hyperbaric physician and your neurologist.

Cost and Practical Considerations

HBOT for TBI requires a significant time and financial commitment:

• Cost per session: commonly quoted at $150 to $400, depending on location, facility type and chamber type.
• Full protocol (40 to 60 sessions): $6,000 to $24,000.
• Insurance coverage: HBOT for TBI is almost never covered by insurance, as it is not FDA-approved for this indication, and Medicare covers HBOT only for its listed indications. Some providers will work with patients on appeals, and VA coverage is available in some cases for veterans.
• Time commitment: 5 days per week for 8 to 12 weeks. Each visit requires 1.5 to 2 hours including setup time. This can be challenging for working patients, and some clinics offer early morning or evening slots.

Prices vary widely by region and by whether a hospital-based wound center or an independent clinic delivers the care. The broader breakdown in how much HBOT costs explains what drives the range and which questions to ask before paying for a package.

How HBOT Compares With Other TBI and Concussion Treatments

HBOT is one of several treatments people with lasting concussion symptoms try, and it is usually added to standard rehabilitation rather than chosen instead of it. The table compares the main options by what each one targets and how settled its evidence is for brain injury.

Because TBI symptoms often overlap with depression, PTSD and sleep problems, many patients combine approaches. The guides to neurofeedback therapy and transcranial magnetic stimulation describe those options, and the overview of treatment options for traumatic brain injury puts them side by side with conventional care.

How to Find an HBOT Provider for TBI

A good HBOT provider for brain injury is supervised by a physician trained in undersea and hyperbaric medicine, runs medical-grade chambers that reach at least 1.5 ATA, and is willing to coordinate with your neurologist, physiatrist or neuropsychologist. Chamber operators often hold certified hyperbaric technologist (CHT) credentials, and many programs follow safety standards from the Undersea and Hyperbaric Medical Society (UHMS).

1. Confirm the medical oversight: Ask who screens patients, who is on site during sessions and how emergencies such as a seizure are handled.
2. Ask about the protocol: Ask for the pressure, session length and number of sessions, and which published study the plan follows.
3. Ask how progress is measured: Baseline and follow-up cognitive testing, symptom scales and, where available, perfusion imaging help you judge whether the course is working.
4. Get the full cost in writing: Ask what a package includes and what happens if you stop early.

You can compare providers in the national directory of hyperbaric oxygen therapy clinics, filter by state, and read each profile before you call. Listing order on Regenerated.com is not paid ranking, and Featured slots are clearly labeled and capped. Verified means a clinic completed our credential checks, not that it paid for placement, and Regenerated.com is free for patients. Inclusion in the directory is not an endorsement, and how Featured, Verified and organic listings differ explains each label. For background on the treatment itself before you contact a clinic, see the hyperbaric oxygen therapy treatment guide.

Key Takeaways: What the Evidence Says About HBOT for TBI

Frequently Asked Questions

Is HBOT FDA-approved for TBI or concussion?

No. As of 2026, HBOT is not FDA approved for traumatic brain injury or concussion, so clinics offer it off label based on a growing but mixed body of research. Hyperbaric chambers are cleared for a short list of conditions recognized by the Undersea and Hyperbaric Medical Society, such as non-healing diabetic wounds, carbon monoxide poisoning and decompression sickness, and TBI is not on that list. The current list is covered in FDA-cleared HBOT indications.

How many HBOT sessions are needed for TBI?

Most published TBI protocols use 40 to 60 sessions, delivered five days a week over 8 to 12 weeks at 1.5 to 2.0 ATA. The positive Israeli trials and the US military trials both used about 40 sessions, so a short series of 5 or 10 trial sessions does not match any studied protocol. If you decide to try HBOT for brain injury, plan for the full course and agree in advance on how progress will be measured.

Can HBOT help years after a brain injury?

It may. Studies from the Efrati research group in Israel, including Boussi-Gross et al. (2013), reported cognitive and perfusion gains in people treated 1 to 5 or more years after their injury. That suggests the brain keeps some capacity for repair long after the usual recovery window. US military sham-controlled trials in people with persistent symptoms were less encouraging, so expectations for late treatment should stay realistic.

Are there any risks or side effects of HBOT for TBI?

Yes, although HBOT is generally well tolerated at the 1.5 to 2.0 ATA pressures used for TBI. The most common side effects are ear pressure or pain during compression, sinus discomfort, a temporary shift toward nearsightedness and fatigue after sessions. Oxygen toxicity seizures and lung barotrauma are rare. An untreated collapsed lung rules HBOT out, and some medications, recent surgery and seizure disorders need review by a hyperbaric physician first.

Does insurance cover HBOT for concussion or TBI?

Usually not. Because HBOT is not FDA approved for brain injury, Medicare and most private insurers treat it as investigational for TBI and do not pay for it, so most patients pay cash. A full course is commonly quoted at $6,000 to $24,000. Some veterans have obtained coverage through the VA, and some providers help patients file appeals, but approval is the exception rather than the rule.

Is a mild hyperbaric chamber the same as HBOT for TBI?

No. Soft-sided mild chambers typically reach about 1.3 ATA and often deliver air or concentrated oxygen rather than 100% oxygen, while TBI studies used medical-grade chambers at 1.5 ATA or higher with 100% oxygen. Results from the brain injury trials cannot be assumed to apply to mild chambers. If a clinic offers HBOT for TBI, ask which chamber type and pressure it uses.

Related Reading

HBOT for brain injury is one part of a larger set of oxygen-based therapies. For a broader overview of hyperbaric oxygen therapy, including approved and off-label uses, how to find a reputable provider and what to expect, read our pillar guide: Hyperbaric Oxygen Therapy: The Complete Patient Guide.

For the study-by-study numbers behind the trials above, see HBOT for TBI and concussion: the clinical data.