Hyperbaric Oxygen Therapy for Traumatic Brain Injury and Concussion: What the Evidence Shows

Most people recover from a concussion, or mild traumatic brain injury, within weeks. A smaller group lives with symptoms for months or years: headaches, poor concentration, memory trouble, irritability, dizziness and sleep problems. These are often called persistent post-concussive symptoms, or post-concussion syndrome.

Three groups ask us about HBOT most often. Veterans and their families, because blast injuries are common in military service and often overlap with post-traumatic stress disorder (PTSD). Parents of young athletes, after a concussion that isn't clearing up. And adults still struggling years after a car accident or fall.

The idea behind the research is a hypothesis, not an established fact. Some researchers propose that injured brain tissue can remain "stunned" but alive, and that repeated sessions of pressurized oxygen might support new blood-vessel growth and the brain's ability to rewire itself. Similar ideas appear in similar neuroplasticity claims in stroke. The trials below were designed to test whether that translates into people feeling and functioning better.

In a drug trial, the placebo is a sugar pill. In a hyperbaric trial, it's much harder to design a fake treatment. People can feel pressure in their ears, so a chamber at normal pressure would quickly give the game away.

The military trials solved this by pressurizing the sham chamber slightly, to 1.2 or 1.3 ATA, while participants breathed ordinary air. That feels similar enough to keep people blinded. You can read more about what "sham" and "ATA" mean in our glossary, and about 1.3 ATA chambers in our mild-versus-medical comparison.

Two ways to read the results

Here is the problem. In the sham-controlled trials, both groups got better. Researchers read that in two very different ways:

• Reading one: both arms were active. A slightly pressurized chamber still raises oxygen in the blood a little. If so, the sham group was receiving a low dose of treatment, and the similar improvement suggests HBOT, even at low doses, has an effect.
• Reading two: both arms were placebo. Daily sessions, attention from staff, structure and expectation can all make people feel better. If so, the similar improvement suggests HBOT itself added nothing beyond that.

Both readings are argued by serious researchers. What would settle it is a control group that is truly inactive and still blinded, and that has proved very hard to build. Until then, the fairest summary is that HBOT has not been shown to do better than a sham chamber in adults with persistent concussion symptoms.

Much of the strongest TBI research was funded by the military, so the VA and Department of Defense positions carry weight.

The VA does not provide HBOT for TBI or PTSD as standard care. Its 2021 evidence brief concluded that HBOT did not lead to short-term improvement in post-concussion or PTSD symptoms compared with sham in people with chronic mild TBI. The Defense Health Agency's 2025 information paper likewise does not recommend HBOT as standard care, while acknowledging the ongoing sham debate.

Some veterans have accessed HBOT through limited pilot or community programs, state-funded programs, or clinical trials. Availability changes, so check directly with the VA before relying on any program. For standard care, the VA's Polytrauma System of Care and local Vet Centers are the places to start.