Long COVID and Hyperbaric Oxygen: A Careful Look at the Evidence

Long COVID — the fatigue, brain fog, and other symptoms that persist months after infection — has left millions searching for relief and few proven treatments. Hyperbaric oxygen became one of the most-discussed options, and it's a revealing example of how to hold promising and cautionary evidence at the same time.

The encouraging trials

A sham-controlled randomized trial from Efrati's group reported that 40 HBOT sessions produced significant improvements in cognitive symptoms, fatigue, sleep, psychiatric symptoms, and pain in long COVID patients — and a one-year follow-up found many of those gains persisted (Zilberman-Itskovich et al.; Hadanny et al., Scientific Reports, 2024). Several smaller studies and case series reported similar subjective improvements. The proposed mechanism fits the broader HBOT picture: reducing inflammation and improving oxygen delivery and brain perfusion in tissue affected by the illness.

The cautionary trial

But rigorous skepticism is warranted, and one trial makes the case. Researchers ran a randomized, placebo-controlled, double-blind study of 101 patients, comparing several oxygen-and-pressure combinations — precisely because HBOT is expensive and, as the authors noted, long COVID symptoms are especially prone to placebo effects. Trials like this exist because early enthusiasm needs to be tested against a genuine placebo before anyone can be confident the effect is real rather than the product of expectation and attention.

Reading it honestly

So where does that leave a patient? There is real randomized-trial evidence of benefit, including durable improvements — genuinely more than exists for many long COVID treatments. There is also legitimate concern about placebo effects and a need for larger, independent confirmation. "Emerging" captures it: promising enough to discuss seriously with a physician, not so settled that anyone should promise you results. If a clinic markets HBOT as a proven long COVID cure, they've gotten ahead of the evidence; if a physician offers it as a reasonable, evidence-informed option with honest uncertainty attached, that's fair medicine.

This article is for general education and is not medical advice. Hyperbaric oxygen therapy has recognized medical uses and real contraindications; whether it is appropriate for you is a decision for you and a qualified physician. At Sync Hyperbaric, all treatment requires a physician's order following an evaluation.