Hyperbaric oxygen
Mixed findingsWhy it might help
Breathing near-100% oxygen under increased pressure raises tissue oxygenation; researchers hypothesize this may reduce neuroinflammation, improve cerebral blood flow and endothelial function, and support neuroplasticity.
What the research shows
Small sham-controlled trials of hyperbaric oxygen have reported improvements in cognition, fatigue, sleep, and pain in some people with long COVID, but a later placebo-controlled trial using far fewer sessions found no benefit over sham. The evidence is genuinely mixed and far from settled.
Sources & what they found (2)
Hyperbaric oxygen therapy improves neurocognitive functions and symptoms of post-COVID condition: randomized controlled trial — Scientific Reports (PMC), 2022
Randomized, double-blind, sham-controlled trial (73 participants, 40 sessions) reporting improved cognition, fatigue, sleep and pain interference.
Ten sessions of hyperbaric oxygen versus sham in patients with long covid (HOT-LoCO): a randomised, placebo-controlled, double-blind, phase II trial — eClinicalMedicine (PMC), 2025
Placebo-controlled trial (10 sessions) that found no short-term benefit over sham, with both groups improving.
Graded claim from the Praxium evidence graph
HBOT (2.0 ATA, 40 sessions) improves fatigue, cognitive function, QoL, and cardiopulmonary function in long COVID, consistent across a systematic review and a large prospective registry.
How strong the finding is
MDPI Life 2024 SR PMC11051078 (10 studies, 3 complete RCTs); Nature Sci Reports 2025 registry n=232. Source: PMC11051078. Dossier claim id hbot-h15. ATA 2.0 (HARD).
What complicates this
Evidence growing; one interim RCT logged 60% AE rate (mostly mild ear discomfort). Condition-specific at 2.0 ATA.
Sources (2)
Zoccali et al. 2026 — Hyperbaric Oxygen Therapy on Long COVID Symptoms: A Breath of Fresh Air — Diseases (PMID 41745098) · 2026-02-07
van Berkel et al. 2025 — Hyperbaric oxygen therapy for long COVID: a prospective registry — Scientific Reports (PMID 40759992) · 2025-08-04



