The HBOT evidence base moved fast in 2024 and 2025. New trials landed for PTSD, long COVID, and pain. Older uses got fresh reviews. And some wellness claims took hits.
Most posts cherry-pick one trial. Patients deserve the whole picture. This list ranks ten studies by method strength and clinical reach.
Each entry covers authors, year, condition, sample size, the key finding, and an evidence tier. PubMed IDs link where we have them. No spin.
At a Glance: 10 Recent HBOT Clinical Studies
| Rank | Study | Condition | Sample Size | Verdict |
|---|---|---|---|---|
| 1 | Doenyas-Barak/Efrati 2024 | Combat PTSD | 63 veterans | Best new PTSD signal |
| 2 | Hadanny 2024 | Long COVID follow-up | 73 patients | Durable QoL gains |
| 3 | Boussi-Gross 2024 | Fibromyalgia (CSA) | 64 women | Large effect size |
| 4 | Buckley/Bennett 2022 Cochrane | Acute CO poisoning | 7 RCTs / 1361 | Still inconclusive |
| 5 | Damineni 2025 | Diabetic foot ulcers | 6 studies / 391 | Healing benefit holds |
| 6 | Marx Protocol (HOPON 2020) | Osteoradionecrosis | 144 patients | Mixed RCT data |
| 7 | Bennett Cochrane 2012/2016 | Sudden hearing loss | 7 RCTs / 392 | Modest benefit, time-sensitive |
| 8 | Denham 2025 | Acute sports concussion | 11 athletes | Promising but small |
| 9 | Xiong 2025 | Autism spectrum | 7 RCTs meta | Effect contested |
| 10 | Kjellberg 2023 | Fibromyalgia | 49 women | Replicates pain benefit |
1. Doenyas-Barak/Efrati 2024 — Combat PTSD RCT (Verdict: Best new PTSD signal)
The top HBOT trial of 2024 came out of the Sagol Center at Shamir Medical Center. Doenyas-Barak, Efrati and team randomized 63 male combat veterans with PTSD to 60 HBOT sessions or sham, then measured symptoms and brain links.
The HBOT arm cut CAPS-5 PTSD scores, depression, and anxiety. Sham patients showed no change. About 68% of treated vets met responder criteria.
What sets this trial apart is the imaging. Functional MRI showed better links in fear-related brain networks. Published in the Journal of Clinical Psychiatry 2024;85(4):24m15464, it is the best sham-controlled PTSD trial so far.
Evidence tier: Randomized sham-controlled trial. Male-only sample and single research site are the main gaps.
2. Hadanny 2024 — Long COVID Long-Term Follow-Up (Verdict: Durable QoL gains)
The Sagol team also put out long-term follow-up from their long COVID RCT. After the first 40-session round, 73 patients were re-tested at one year.
SF-36 quality-of-life gains held up across most areas. Sleep stayed better than baseline. Cognitive gains held too.
Most long COVID care fades fast. The Hadanny data hints HBOT-driven plasticity may stick. A 2024 registry from the same group covered 232 long COVID patients.
Evidence tier: RCT with one-year follow-up. Outside-Israel replication is still pending.
3. Boussi-Gross 2024 — Fibromyalgia After Childhood Sexual Abuse (Verdict: Large effect size)
Boussi-Gross and team randomized 64 women with CSA-linked fibromyalgia to 60 HBOT sessions at 2.0 ATA or drug care. The HBOT arm won. See the fibromyalgia evidence atlas for the full investigational evidence breakdown.
Widespread Pain Index fell by 4.5 points with a Cohen's d of 0.97 between groups. The Fibromyalgia Impact Questionnaire fell 24.3 points, d = 1.27. Both are large effects.
Brain scans showed less pain-network activity after care, which points to a central effect, not placebo. The trial ran in Scientific Reports.
Evidence tier: Randomized controlled trial (active comparator). Single-center; outside-Israel replication matters before wide use.
4. Buckley/Bennett 2022 Cochrane — Acute CO Poisoning (Verdict: Still inconclusive)
Carbon monoxide is the most contested HBOT use. The Cochrane review by Buckley, Bennett and team pooled seven RCTs covering 1,361 patients and found the evidence was too weak to confirm benefit.
A 2026 Fujita meta-analysis reached the same call. No clear cut in deaths. No clear nerve-injury benefit.
Yet UHMS still backs HBOT for acute CO, citing the Weaver 2002 trial. Most US poison centers refer high-risk cases (loss of consciousness, heart effects, pregnancy). Cochrane calls for a clear multi-site RCT, but none has come.
Evidence tier: Systematic review of RCTs. Trial-to-trial mixing is the core problem.
5. Damineni 2025 — Diabetic Foot Ulcer Update (Verdict: Healing benefit holds)
The 2025 Damineni systematic review used Cochrane methods to pool six studies covering 391 diabetic foot ulcer patients. The signal lines up with prior reviews.
HBOT-treated ulcers healed at higher rates. Major amputation rates fell. Ulcer size and depth dropped versus wound care alone.
The open debate is which Wagner grades benefit most. A 2024 Wagner-graded meta-analysis found the best signal in Wagner 3 and 4 ulcers — the grades CMS covers under NCD 20.29.
Evidence tier: Systematic review of RCTs and observational studies. Mixed session counts limit pooled effect math.
6. Marx Protocol / HOPON Trial — Osteoradionecrosis (Verdict: Mixed RCT data)
The Marx Protocol — 30 pre-op sessions at 2.4 ATA plus 10 post-op — has been the head-and-neck standard for decades. Real-world cure rates top 95%.
But the UK HOPON RCT pushed back with mixed data. A 2016 Cochrane review by Bennett on late radiation tissue injury found HBOT helps head-and-neck ORN cases but stays unclear for other sites.
A 2020 review at MD Anderson covering 144 ORN patients found staged surgery with HBOT cut post-op infection and dehiscence.
Evidence tier: Mixed — RCT plus large retrospective cohorts. Marx Protocol remains the practical standard, as detailed by community hyperbaric centers reviewing the 2021 update.
7. Bennett Cochrane — Idiopathic Sudden Sensorineural Hearing Loss (Verdict: Modest benefit, time-sensitive)
The Cochrane review by Bennett on HBOT for sudden hearing loss pooled seven RCTs covering 392 patients. The pooled effect favored HBOT for hearing gain, mostly when started within two weeks. See the sudden sensorineural hearing loss evidence atlas for the full study-by-study evidence breakdown.
UHMS added ISSHL to its approved list in 2014 on this data. The American Academy of Otolaryngology guideline says to consider HBOT within two weeks of onset.
A 2024 comparison study showed earlier and longer plans beat late ones. The signal is real but small in size.
Evidence tier: Systematic review of RCTs. Time from onset is the top driver.
8. Denham 2025 — Acute Sports Concussion (Verdict: Promising but small)
Dr. Daphne Denham's 2025 study in Undersea and Hyperbaric Medicine treated 11 student athletes with acute concussion. HBOT was set at 1.5-2.0 ATA, twice daily, 70 minutes each.
Baseline median scores on an FDA-cleared EEG biomarker were 18. After a median of three sessions, scores jumped to 84 — into the non-concussed range. Most athletes returned to play in days.
This is hypothesis-building, not proof. No control arm. Small N. But a 2025 meta-analysis of 299 athletes showed HBOT sped up recovery from muscle injury (p<0.0001). RCTs in acute sport concussion are not yet out.
Evidence tier: Open-label case series. Larger RCTs are needed before guidelines change. Iowa HBOT centers covered the protocol soon after the 2025 paper.
9. Xiong 2025 — Autism Spectrum Meta-Analysis (Verdict: Effect contested)
The cleanest recent autism data comes from a 2025 systematic review and meta-analysis that searched seven databases through March 2024. The take is honest about the mess.
Some trials showed symptom cuts. Others showed nothing. A 2016 Cochrane review on ASD found no proof HBOT helps core symptoms and flagged minor ear barotrauma as a real event.
The honest read: HBOT is not first-line care for autism. Parents who try it should know the data is mixed at best, and good centers will say so. A 2024 second look found verbal-score gains, but only in subgroups.
Evidence tier: Systematic review of mixed-quality RCTs. Trial mixing blocks firm claims.
10. Kjellberg 2023 — Fibromyalgia Replication (Verdict: Replicates pain benefit)
Outside replication is the best sign an effect is real. A 2023 Scandinavian fibromyalgia trial randomized 49 women and matched the pain-cut signal from prior Israeli work.
HBOT at 2.4 ATA over 40 sessions helped both pain scores and quality of life. Effect sizes were smaller than in Boussi-Gross, likely because baseline symptoms were milder.
With the 2024 Israeli RCT, fibromyalgia now has the cleanest replication of any off-label HBOT use. Insurance still does not cover it. But the data supports careful clinical interest at expert centers.
Evidence tier: Randomized controlled trial. International replication strengthens the prior signal, and a 2024 chronic-pain systematic review pooled across multiple HBOT pain trials reached the same direction of effect.
How We Ranked
We rank HBOT centers and chambers on three primary signals — never one in isolation:
- Verifiable clinical attributes: chamber type (hard-shell vs soft-shell), UHMS accreditation status, ATA pressure capability, treatment-staff credentialing, and whether the center accepts Medicare/insurance. Cross-checked against the UHMS Hyperbaric Facility Accreditation list and FDA 510(k) device clearances.
- Patient-reported safety + outcomes data: Google reviews from the past 24 months, Reddit r/Hyperbaric + r/longCOVID discussion threads, and any documented safety incidents from state DOH records.
- Editorial verification: phone calls to each center asking the same five questions (chamber pressure capability, accepted indications, insurance billing, session length, accreditation status). We log responses, including non-responsive practices.
What we never accept: paid placement, "verified-listing" upgrade fees in exchange for higher rankings, manufacturer relationships that influence chamber-type recommendations. Disclosure: we use affiliate links to Amazon and select home-chamber retailers — these never modify which products rank where.
Update cadence: monthly review for chambers, quarterly for clinics. Last-updated date at the top of every article. Report inaccuracies to research@hyperbaricfinder.com — corrections shipped within 72 hours.
Frequently Asked Questions
Which 2024 HBOT study is the strongest by method?
The Doenyas-Barak/Efrati combat PTSD trial is the top new RCT. It was sham-controlled, used 63 patients, paired clinical scores with MRI imaging, and ran in the Journal of Clinical Psychiatry. The mix of clinical and imaging endpoints sets it apart.
Did any 2024-2025 study disprove an HBOT use?
The 2026 Fujita meta-analysis on acute CO poisoning matched the prior Cochrane finding of weak evidence. No 2024 study gave a clean disproof, but autism and acute CO both still lack confirming data.
Why does HBOT keep failing CO trials if UHMS still backs it?
Trial mixing is the main issue. Studies use different doses, enroll at different time points, and track different outcomes. UHMS bases its call on Weaver 2002, the largest single positive trial. No clear multi-site replication has come.
Are any HBOT trials looking at GLP-1 or peptide mixes?
No published RCTs pair HBOT with GLP-1 drugs or peptides as of mid-2026. Some preclinical work pairs HBOT with growth-factor adjuncts. Combo trials would need careful safety review first.
Should I trust a clinic that cites the 2024 PTSD study for wellness HBOT?
Be cautious. The Efrati protocol uses 60 sessions at set pressures, with imaging follow-up, in screened vets. Wellness clinics offering 5-10 sessions for "general well-being" do not deliver the studied care. Ask which trial protocol your clinic actually runs.
Related Reading: For coverage of regulatory standing, see our Top 10 FDA-Approved HBOT Conditions guide. For protocol details, the HBOT Insurance Coverage breakdown covers billing for the 14 UHMS indications. For long COVID specifically, see our Long COVID Research Update.
-- The HBOT Finder Team