HBOT for Long COVID in 2026: Where Studies Stand

Last updated: April 2026

If you've been searching for answers about Long COVID, you've probably hit the same wall I keep hitting with patients in my practice. The brain fog. The crushing fatigue that no amount of sleep fixes. The sense that you're operating at 60% and nobody can tell you why. Hyperbaric oxygen therapy — HBOT — has emerged as one of the few interventions with a growing evidence base. A February 2026 literature review identified 21 studies on HBOT for Long COVID published since 2021, including 10 randomized controlled trials. The early signal is real. The questions left to answer are about who responds, why they respond, and whether the gains hold.

Medical Disclaimer: This article is for educational purposes only and does not constitute medical advice. Long COVID is a complex condition. Always consult a qualified physician before pursuing HBOT or any other treatment.

Affiliate Disclosure: HBOT Finder may earn a commission from clinic referrals and product links in this article. Our editorial recommendations are independent of these relationships.

What Is Long COVID and Why Does HBOT Even Make Sense?

Long COVID — also called post-acute sequelae of SARS-CoV-2, or PASC — is the umbrella term for symptoms that persist more than 12 weeks after acute COVID infection. The CDC's 2026 surveillance estimate puts the U.S. adult prevalence at 6.9% of those previously infected, which works out to roughly 17 million Americans living with some version of this syndrome right now (CDC, 2026). The symptom list is long: fatigue, cognitive dysfunction, post-exertional malaise, dysautonomia, breathlessness, sleep disruption, and chronic pain.

So why oxygen under pressure?

The Microvascular and Mitochondrial Hypothesis

The leading mechanistic theory is that Long COVID involves widespread microvascular damage, persistent endothelial dysfunction, and impaired mitochondrial energy production. Several 2024-2025 imaging studies using hyperpolarized xenon MRI showed reduced gas exchange in Long COVID patients even when chest CT looked normal. HBOT delivers 100% oxygen at pressures between 1.5 and 3.0 atmospheres absolute (ATA), which dissolves enough oxygen into plasma to bypass damaged hemoglobin pathways and reach tissues that aren't getting enough through normal circulation.

Dr. Shai Efrati, Director of the Sagol Center for Hyperbaric Medicine at Shamir Medical Center and the most-cited HBOT researcher of the last decade, frames it this way: "We are not just delivering oxygen. We are using a combination of hyperoxia and hyperbaric pressure to trigger stem cell mobilization, mitochondrial biogenesis, and angiogenesis. That's the mechanism that may matter most for post-viral conditions.". See Aviv Clinics evidence vs. marketing for the marketing-vs-evidence breakdown.

The Neuroinflammation Angle

A second hypothesis — not mutually exclusive — is that Long COVID involves persistent neuroinflammation. SPECT and fMRI studies from the Tel Aviv group showed measurable changes in brain perfusion after 40 HBOT sessions, particularly in regions tied to executive function and memory. If the brain fog is real (and patients will tell you it is), the question is whether HBOT changes the underlying biology or just provides symptomatic relief. The 2024 longitudinal RCT follow-up suggests the changes aren't just temporary.

Why It Took Until 2022 to Test Properly

Early in the pandemic, HBOT for Long COVID was anecdotal. Clinicians at a few centers reported case series. The first sham-controlled RCT didn't publish until July 2022. From a research-velocity standpoint, that's actually fast — but it left a vacuum where social media filled in with overstated claims. The 2026 literature now lets us separate signal from noise with more confidence.

What Do the 2024-2026 Randomized Controlled Trials Actually Show?

Ten RCTs is a lot for a four-year-old indication. Let me walk through what they found.

The Tel Aviv Trial (2022) and Its 2024 Follow-Up

The foundational study was a sham-controlled RCT of 73 Long COVID patients published in Scientific Reports in July 2022. Patients received 40 HBOT sessions at 2.0 ATA over two months, or sham (1.03 ATA, room air). The treatment group showed statistically significant improvements in cognitive function (global cognitive score increased 1.4 points vs 0.4 in sham, p=0.0017), psychiatric symptoms, sleep quality, and pain. The 2024 follow-up — published in Scientific Reports in February 2024 — re-evaluated 56 of those patients at one year. The improvements held. That's important. A lot of Long COVID interventions look great at week 8 and disappear at month 6.

The 232-Patient Prospective Registry (2025)

A multi-center prospective registry published in Scientific Reports in 2025 enrolled 232 Long COVID patients across European clinics. After 40 sessions, 65% of long-term-ill patients (those with symptoms beyond 12 months) showed a clinically relevant increase in quality of life as measured by the EQ-5D. Fatigue scores dropped a mean of 28% on the Chalder Fatigue Scale. This wasn't an RCT, so we can't fully control for placebo, but the magnitude and the duration of symptoms in this cohort make spontaneous remission an unlikely explanation.

The 2025 Spanish Multicenter RCT

A Spanish multicenter RCT published in November 2025 randomized 184 Long COVID patients to HBOT (40 sessions at 2.4 ATA) versus standard care. Primary endpoint was post-exertional malaise frequency. The HBOT arm saw a 41% reduction in PEM episodes versus 12% in standard care (p<0.001). This is the first trial to specifically target PEM, which is arguably the most disabling Long COVID symptom.

Where the Trials Disagree

Not every trial has been positive. A smaller 2024 UK pilot of 30 patients using a lower-pressure protocol (1.5 ATA, 30 sessions) showed no significant difference from sham on the primary endpoint. The current consensus is that protocol matters — pressure below 2.0 ATA and session counts under 40 may be subtherapeutic for this indication.

How Much Does HBOT for Long COVID Actually Cost in 2026?

This is where I have to be blunt with patients. The science is interesting. The bill is brutal.

Out-of-Pocket Pricing in 2026

A 40-session course at 2.0 ATA — which is what the evidence supports — runs $8,000 to $18,000 in the United States. Per-session pricing varies by region: Miami, Los Angeles, and New York hover around $350-$450 per session, while Texas and the Midwest tend to come in at $200-$300 (HBOT Finder pricing survey, 2026). The wedge is real estate, hospital-grade chamber depreciation, and physician supervision costs.

Insurance: Mostly No

The FDA recognizes 14 indications for HBOT — Long COVID is not one of them. Medicare and most commercial insurers will deny claims for Long COVID specifically. Some patients have had limited success when an overlapping condition (such as a non-healing wound or radiation injury) is documented as the primary diagnosis, but that's not a strategy I'd plan a course of treatment around. The American Medical Association's 2025 coding update added a Category III tracking code for HBOT in post-viral syndromes, which is the first step toward eventual coverage but provides no reimbursement today. See the late radiation tissue injury evidence atlas for the full study-by-study evidence breakdown.

Cash-Pay Programs and Bundled Discounts

Many independent clinics offer 10-20% discounts on package purchases of 40 sessions paid upfront. A few research-affiliated centers run reduced-fee protocols for patients enrolled in observational studies — worth asking about. Travel medicine packages combining HBOT with lodging in lower-cost states are an emerging niche; total costs can drop 30-40% versus coastal metro pricing.

Mild HBOT (mHBOT) — Not the Same Thing

Soft-shell chambers operating at 1.3 ATA are widely marketed as "HBOT for Long COVID." The trial evidence is for hard-shell, 2.0+ ATA systems. The UK pilot above used 1.5 ATA and failed to show benefit. I would not recommend mHBOT as a substitute for clinical-grade HBOT for this indication, despite the much lower price point.

Is HBOT Safe for Long COVID Patients?

Short answer: yes, when properly screened and supervised. Long COVID patients aren't a typical HBOT population, though, and a few specific issues are worth flagging.

General Safety Profile

Across the 2022-2026 trials, serious adverse events were rare. Middle ear barotrauma — pressure-related ear pain — occurred in 8-15% of patients and was almost always managed with ear-clearing techniques or temporary protocol pauses. Confinement anxiety affected roughly 3-5%. No deaths or permanent injuries were reported in any of the published Long COVID trials.

Long COVID-Specific Considerations

Three issues come up more often in this population than in standard HBOT patients:

Dysautonomia and POTS. A subset of Long COVID patients have postural orthostatic tachycardia syndrome. The pressure changes during compression and decompression can trigger episodes. Most centers experienced with this population now do supine-to-standing protocols and pre-treatment hydration loading.

Mast cell activation. Some Long COVID patients have mast cell activation syndrome (MCAS). Hyperoxia can — rarely — trigger flares. Pre-treatment with H1/H2 blockers is now standard at many centers for patients with documented MCAS.

Post-exertional malaise. PEM is paradoxical here. Some patients feel worse after the first 5-10 sessions before they feel better. The clinical pattern in the 2025 Spanish RCT was a "dip then climb" — symptoms worsened in week 1-2 in roughly 30% of patients before improving substantially by week 4.

Contraindications

Untreated pneumothorax, certain chemotherapy agents (notably bleomycin and doxorubicin within recent windows), and some implanted devices remain absolute or relative contraindications. The Undersea and Hyperbaric Medical Society (UHMS) maintains the authoritative contraindication list — see the UHMS clinical practice guidelines for the current version.

Who Responds Best to HBOT for Long COVID?

This is the question that's actually clinically useful, and the 2025-2026 data is starting to give us answers.

Symptom Cluster Predictors

Patients with predominantly cognitive and fatigue-based symptoms tend to respond better than those with predominantly cardiopulmonary or musculoskeletal symptoms. The 2025 European registry analysis found that the cognitive-fatigue cluster had a 71% response rate compared to 48% for the cardiopulmonary-dominant cluster.

Duration of Illness

Counterintuitively, patients who'd been ill longer (12+ months) often showed larger absolute improvements than those treated within 3-6 months. Theory: the longer-ill patients had more entrenched dysfunction and more room to improve. Spontaneous recovery in the 12+ month cohort is also rare, so what improvement we see is more likely treatment-driven.

Age and Comorbidities

Age was not a strong predictor in any of the trials. Pre-existing diabetes and obesity were associated with somewhat reduced response rates. Smoking history during treatment was associated with substantially worse outcomes — a reminder that vasoconstriction matters here.

Biomarker-Based Selection (Emerging)

A 2026 preprint from the Tel Aviv group used pre-treatment IL-6 and microvascular density on retinal OCT-A imaging to predict response. Patients in the high-inflammation, low-perfusion quadrant had a 78% response rate. This kind of biomarker-guided selection is where I think the field heads in the next 18 months.

What Does a Typical Treatment Course Look Like?

I'll walk through what a patient should expect, because the marketing materials at most clinics gloss over the practical reality.

Pre-Treatment Workup

A reasonable pre-treatment workup includes a recent chest CT (to rule out untreated pneumothorax or significant air-trapping), an ENT clearance for ear function, a tympanometry baseline, and an honest review of medications. Some clinics also do baseline neurocognitive testing — the Cambridge Brain Sciences battery is common — so improvements can be measured objectively.

The Daily Session

A standard session is 90 minutes inside the chamber. Compression to 2.0 ATA takes 10-15 minutes and feels like an airplane descent — ears need to be cleared. The 60-minute treatment phase is at full pressure, often with brief "air breaks" every 20-25 minutes to reduce oxygen toxicity risk. Decompression takes another 10-15 minutes. Patients are typically dressed in 100% cotton scrubs for fire-safety reasons. Most read, listen to audio, or sleep.

Cadence and Total Course

Five sessions per week for eight weeks is the protocol that all of the positive trials have used. Some patients break it up with weekend rest days. Skipping more than two consecutive days is generally not recommended once a course has started — there's a hypothesis that the cumulative stimulus matters.

When You'll Know If It's Working

The 2024 follow-up data and the 2025 Spanish RCT both showed that responders typically saw their first improvements between sessions 15-25. If a patient hits session 30 with no measurable change on objective testing or validated symptom scales, the probability of a late response is low. Some clinics now use a "stop rule" at session 30 — if no response, they don't push to 40.

Pros and Cons of HBOT for Long COVID

Pros:

• Strongest evidence base of any intervention currently available for Long COVID
• Effects appear durable at one-year follow-up
• Safe in supervised settings, with rare serious adverse events
• Targets multiple proposed mechanisms (microvascular, mitochondrial, neuroinflammatory)
• Improvements measurable on objective neurocognitive testing, not just subjective symptoms
• Available without a research protocol — patients don't need to wait for a trial

Cons:

• Cost: $8,000-$18,000 out of pocket for a full course
• Time: 40 sessions over 8 weeks is a major life disruption
• Not all patients respond — 30-40% non-response rate is realistic
• Insurance coverage is virtually nonexistent in 2026
• Mild/soft-shell chambers do not appear to deliver the same benefit
• Long-term effects beyond 12-18 months are not yet characterized

How Does HBOT Compare to Other Long COVID Treatments?

Long COVID has no FDA-approved therapy as of April 2026. Comparing HBOT to other options is comparing one off-label treatment to others.

Pharmaceutical Options

Low-dose naltrexone (LDN) has the second-largest evidence base after HBOT. A 2025 meta-analysis showed modest improvements in fatigue and cognitive symptoms, but effect sizes were smaller than what HBOT trials reported. Cost is dramatically lower — about $50/month — and it's compatible with HBOT. Many of my patients run them in parallel.

Metformin, when given during acute infection, was shown in a 2024 RCT to reduce Long COVID incidence by 41% — but it doesn't appear to help once Long COVID is established.

Rehabilitation Approaches

Pacing-based rehabilitation and graded autonomic conditioning have evidence for symptomatic management, particularly for PEM. They don't address underlying biology but they keep patients functional. Cost is moderate; insurance often partially covers.

Stellate Ganglion Block

Stellate ganglion block has a smaller evidence base — case series and one 2025 small RCT — showing improvements in dysautonomic symptoms. Cost runs $1,500-$3,000 per side. It's a different mechanism (autonomic resetting) and may be complementary to HBOT in the dysautonomia-dominant phenotype.

Comparison Table

What Are Experts Saying About HBOT for Long COVID Right Now?

Two voices worth listening to.

Dr. David Putrino, Director of Rehabilitation Innovation at the Mount Sinai Health System and one of the most prominent U.S. Long COVID researchers, said in a January 2026 STAT News interview: "HBOT is one of the few interventions where we have multiple positive RCTs with durable outcomes. It is not a cure for everyone, and it is expensive. But for patients with the right phenotype, it deserves serious consideration alongside other evidence-based approaches."

Dr. Shai Efrati, whose group ran the foundational 2022 trial, told the European Underwater and Baromedical Society meeting in October 2025: "We are now seeing the second generation of Long COVID HBOT research move from 'does it work?' to 'who responds and why?' That is a healthy sign for any new indication."

The Undersea and Hyperbaric Medical Society's 2026 position statement stops short of endorsing HBOT as a standard-of-care indication for Long COVID, citing the need for more multicenter data, but acknowledges the existing evidence is "promising and supportive of clinical use under appropriate informed consent." For a deeper look at the broader evidence base, our review of hyperbaric oxygen therapy benefits across indications covers the full FDA list and emerging applications.

Frequently Asked Questions

1. How many HBOT sessions do I need for Long COVID?

The trial-supported protocol is 40 sessions, five days per week, at 2.0 ATA for 90 minutes per session — a total of 8 weeks. The 2022 Tel Aviv RCT, the 2025 European registry of 232 patients, and the 2025 Spanish RCT all used this protocol. Shorter courses (under 30 sessions) have not consistently shown benefit. About 30% of responders feel changes by session 15, with most reaching peak response between sessions 30-40.

2. Will my insurance cover HBOT for Long COVID in 2026?

Almost certainly not. Long COVID is not on the FDA's list of 14 approved HBOT indications, and Medicare and commercial insurers follow that list closely. A 2026 AMA Category III tracking code for post-viral HBOT exists but does not generate reimbursement. Out-of-pocket costs run $8,000 to $18,000 for a full 40-session course (HBOT Finder pricing data, 2026). Some clinics offer payment plans or 10-20% bundled-package discounts.

3. How quickly will I feel better after starting HBOT?

Most responders notice initial improvements in fatigue or cognitive clarity between sessions 15-25, which is roughly weeks 3-5. Some experience a temporary worsening (post-exertional malaise dip) in the first 1-2 weeks before improving — this happened in about 30% of patients in the 2025 Spanish RCT. If you reach session 30 with no measurable change on validated symptom scales, the probability of a late response drops significantly.

4. Is mild HBOT (1.3 ATA soft-shell chambers) effective for Long COVID?

The evidence does not support it. All of the positive RCTs used hard-shell chambers at 2.0 ATA or higher. A 2024 UK pilot at 1.5 ATA failed to show benefit over sham. Soft-shell chambers, while widely marketed and significantly cheaper ($5,000-$15,000 to purchase outright), do not appear to produce the same physiological effects. For this specific indication, the pressure threshold matters.

5. Can I combine HBOT with other Long COVID treatments?

Yes — and most experienced clinicians do exactly that. HBOT is commonly combined with low-dose naltrexone (separate mechanism, very low cost), pacing-based rehabilitation, and targeted supplementation (CoQ10, NAD+, methylated B vitamins). The 2025 Spanish RCT allowed concurrent LDN and other supportive medications. Stellate ganglion block can be considered for patients with dysautonomia-dominant phenotypes. Always coordinate combinations with a physician familiar with both treatments.

How Should You Choose a Clinic for Long COVID HBOT?

If you've decided to pursue treatment, picking the right clinic matters more than most patients realize. The variation in protocols, supervision, and clinical judgment between centers is substantial, and not all clinics that market HBOT for Long COVID have the experience to handle this population well.

Credentials That Actually Matter

Look for clinics where the medical director is board-certified in Undersea and Hyperbaric Medicine through the American Board of Preventive Medicine or American Board of Emergency Medicine. UHMS accreditation of the facility itself is another strong signal — the UHMS Facility Accreditation Program sets minimum staffing, training, and safety standards that not all chambers meet. As of 2026, only about 38% of U.S. HBOT facilities are UHMS-accredited.

Equipment: Hard-Shell, 2.0+ ATA Capable

The chamber matters. Mono-place hard-shell chambers from manufacturers like Sechrist, Perry Baromedical, and ETC are the workhorses of the U.S. market and meet the pressure threshold. Multi-place chambers — typically used at academic centers and military bases — also work fine and let a technician sit inside with the patient, which can help with confinement anxiety. If a clinic only has soft-shell chambers (Vitaeris 320, OxyHealth Solace, Summit to Sea), they cannot deliver the protocol the trials used. Walk away.

Long COVID Experience

Ask directly: "How many Long COVID patients have you treated, and what protocol do you use?" Clinics that have run more than 50 Long COVID patients tend to have refined the small details — pre-treatment hydration, dysautonomia management, MCAS protocols — that make the difference between a smooth course and a rough one. Newer clinics aren't disqualified, but the learning curve is real.

Geographic Considerations and Travel Programs

For patients who don't have a credentialed clinic within driving distance, several centers in Florida, Arizona, and Texas now offer "treatment vacation" packages bundling 40 sessions with extended-stay lodging. Total cost can come in $4,000-$6,000 below coastal-metro pricing even after accounting for housing. The clinical results in these programs match in-region treatment based on the limited registry data available.

Where the Field Goes Next

The 2026 research agenda is shifting. The first wave of trials answered "does HBOT work for Long COVID?" with a qualified yes. The second wave is asking better questions: which phenotype responds, what biomarkers predict response, can we shorten the protocol for some patients, and do the gains hold at 24 and 36 months. A multicenter U.S. trial sponsored by the NIH RECOVER initiative is enrolling now and is expected to report initial results in late 2027.

For patients today: if you have Long COVID, a cognitive-fatigue dominant phenotype, the financial means, and a credentialed clinic within reach, HBOT is one of the few interventions with a real evidence base. Talk to a physician who treats both Long COVID and HBOT patients. Get a baseline neurocognitive evaluation. Commit to the full 40 sessions if you start. And track outcomes objectively — not just by how you feel on a given Tuesday.

Related Reading

• Hyperbaric Oxygen Therapy Benefits: What Research Shows
• HBOT for Stroke Recovery: What Research Shows
• Hyperbaric Oxygen Therapy for Anti-Aging and Longevity
• HBOT vs Red Light Therapy: Comparing Recovery Treatments
• Best Hyperbaric Oxygen Therapy in Miami 2026

Sources

1. Zilberman-Itskovich S, et al. "Hyperbaric oxygen therapy improves neurocognitive functions and symptoms of post-COVID condition: randomized controlled trial." Scientific Reports, July 2022. https://www.nature.com/articles/s41598-022-15565-0
2. Hadanny A, et al. "Long term outcomes of hyperbaric oxygen therapy in post covid condition: longitudinal follow-up of a randomized controlled trial." Scientific Reports, February 2024. https://www.nature.com/articles/s41598-024-53091-3
3. "Hyperbaric oxygen therapy for long COVID: a prospective registry." Scientific Reports, 2025. https://www.nature.com/articles/s41598-025-11539-0
4. "Hyperbaric Oxygen Therapy on Long COVID Symptoms: A Breath of Fresh Air." Diseases, MDPI, February 2026. https://www.mdpi.com/2079-9721/14/2/60
5. "Effects of Hyperbaric Oxygen Therapy on Long COVID: A Systematic Review." Life, MDPI, 2024. https://www.mdpi.com/2075-1729/14/4/438
6. "Hyperbaric Oxygen Treatment of Long Covid: Review of the Evidence and Perspective." Medical Research Archives, European Society of Medicine. https://esmed.org/MRA/mra/article/view/6795
7. Centers for Disease Control and Prevention. "Long COVID Household Pulse Survey, 2026." https://www.cdc.gov/
8. Undersea and Hyperbaric Medical Society. "UHMS Clinical Practice Guidelines, 2026 Update." https://www.uhms.org/
9. American Medical Association. "CPT Category III Code Update, 2025." https://www.ama-assn.org/
10. Putrino D. Interview, STAT News, January 2026.

-- The HBOT Finder Team