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Tip · Oxygen

Hyperbaric oxygen therapy (HBOT)

High oxygen pressure – well supported for approved indications. The longevity use rests on a small study without a control group.

Hyperbaric oxygen therapy means breathing oxygen under increased ambient pressure. For several medical indications it is an established procedure; for longevity use it is not. This page answers the question that comes even before efficacy: whether what you are being offered is HBOT at all.

In short

HBOT is a defined term, and the definition excludes most wellness chambers. The Undersea and Hyperbaric Medical Society sets clinical HBOT at more than 1.4 ATA with 100% oxygen; applications below that are explicitly not considered HBOT, the only exception being acute altitude sickness. Almost all recognized indications are treated at 2.0 to 3.0 ATA. Wound healing is the most solidly supported: in diabetic foot ulcers, the healing rate was higher after six weeks, but no longer after one year. The studies used 40 to 60 daily sessions — ten appointments at 1.3 ATA are something else.

What HBOT is — and what is found in many studios

The pressure threshold is not a matter of taste. A narrative review based on a PubMed search from January 1990 to March 2026 and the consensus papers of the professional societies states: clinical HBOT is treatment at more than 1.4 ATA with 100% oxygen. Anything below that is not considered HBOT for medical purposes, except for acute altitude sickness. Soft chambers mostly operate at 1.2 to 1.4 ATA with room air or a concentrator.

The difference is physical. At 2.0 to 3.0 ATA with approximately 100% oxygen, the arterial partial pressure of oxygen often exceeds 1,500 to 2,000 mmHg. Almost all FDA-recognized indications are treated in this range, and this is also where the studies were run that are used to advertise longevity use.

How it works

Under overpressure, the amount of oxygen physically dissolved in plasma follows the ambient pressure; oxygen thus also reaches tissue that is poorly supplied via hemoglobin. For anti-aging use, a second mechanism is central, and it is based not on the amount but on the alternation: the group around Efrati calls it the “hyperoxic hypoxic paradox” — short phases of hyperoxia with interspersed air breaks are said to trigger the same signaling pathways as oxygen deficiency, above all the stabilization of HIF-1α and HIF-2α and, through this, the formation of new blood vessels via VEGF.

The air breaks in the protocol are therefore not a detail but part of the stimulus. How much pressure and how many sessions are needed is, as the same authors write, “still not fully understood”.

The protocol is the real bill

In the cognition study in healthy older adults, it was 60 daily sessions on five days a week over three months, each 90 minutes at 2 ATA; in the long COVID study, 40 daily sessions. For wound indications, a review summarizes 2.0 to 2.5 ATA for 60 to 90 minutes over 20 to 40 sessions. Anyone who books ten sessions does not have a slimmed-down version of the protocol but an untested one.

What is well supported

HBOT has its most reliable evidence base in chronic wounds. A Cochrane review of twelve randomized trials with 577 participants, ten of them with 531 participants on diabetic foot ulcers, found a higher healing rate after six weeks (risk ratio 2.35; 95% CI 1.19–4.62; p = 0.01). An independent meta-analysis of 14 studies with 768 participants additionally found fewer major amputations (RR 0.60; 95% CI 0.39–0.92). The second strong finding: in long COVID, a double-blind, sham-controlled trial with 73 participants showed improvements in cognition, energy and pain interference with effect sizes between about 0.46 and 0.74.

What the studies show

Chronic wounds (Cochrane, Kranke et al. 2015)

Twelve randomized trials with 577 participants, ten of them with 531 participants on diabetic foot ulcers. The healing rate was increased after six weeks (RR 2.35; 95% CI 1.19–4.62; p = 0.01) and no longer detectable after one year. For major amputation, five studies with 312 participants found no significant difference (RR 0.36; 95% CI 0.11–1.18). In short: faster, but not ultimately better.

Long COVID, double-blind and sham-controlled (Zilberman-Itskovich et al. 2022)

73 people with symptoms for at least three months after a confirmed infection, randomized to 40 daily sessions (n = 37) or sham treatment (n = 36). Significant group-by-time interactions for global cognitive function (d = 0.495; p = 0.038), energy (d = 0.522; p = 0.029), psychiatric symptoms (d = 0.636; p = 0.008) and pain interference (d = 0.737; p = 0.001). A follow-up in 31 participants found the improvements again a mean of 486 ± 73 days later, without a control group.

Cognition in healthy older adults (Hadanny et al. 2020)

63 healthy adults over 64, randomized to HBOT (n = 33) or control (n = 30) over three months. The group-by-time interaction for the primary cognitive endpoint was significant (p = 0.0017), most clearly for attention (net effect size 0.745) and processing speed (0.788). The catch is in the methods section: the control arm received “no active intervention as a no-contact group”.

Where the data stop

Of all things, for the indication most often cited as established, the pooled evidence is negative: a Cochrane review of six studies with 1,361 participants on carbon monoxide poisoning found no significant benefit over normobaric oxygen (odds ratio 0.78; 95% CI 0.54–1.12). Two more recent meta-analyses find benefits in individual endpoints, but no consistent overall picture.

For anti-aging use, independent confirmation is missing. The frequently cited telomere finding in 35 healthy adults aged 64 and over comes from a study without a control group — the authors write this themselves — and has never been independently replicated; besides it there is only a case report on a single person. In this paper and in the cognition study it is disclosed that several authors work for AVIV Scientific LTD and that the last author is a shareholder there. That is not an accusation, but it means: the longevity evidence comes from a group with a commercial interest.

How to do it

This is how it was done in the studies: 60 daily sessions on five days a week over three months in a multiplace chamber, each session 100% oxygen via mask at 2 ATA for 90 minutes, with five-minute air breaks every 20 minutes, compression and decompression at 1 meter per minute. Measurements were taken only at least one week after the last session, to rule out acute oxygen effects.

The air breaks are meant to create the alternating stimulus and to lower the risk of oxygen toxicity. That they do the latter is shown by a center’s analysis: before a five-minute air break was introduced, 3.9 seizures per 10,000 treatments; afterwards, 1.2.

Safety

HBOT belongs in a center with hyperbaric chamber experience and a prior medical examination. The only absolute contraindication is an untreated pneumothorax, because it can turn into a tension pneumothorax during decompression; intraocular gas is also absolute. Relative contraindications include COPD, asthma, pulmonary bullae, Eustachian tube dysfunction, seizure disorders, severe claustrophobia and pregnancy. The most common side effect concerns the ears: in a review of 54 studies with 18,284 patients, 15% had an otological event, and of the middle ear barotraumas 6.4% were severe; the most important protective factor was the pressure equalization technique. Seizures are rare — 43 in 188,335 sessions — but not harmless: one death afterwards has been documented. Side effects overall are pressure- and dose-dependent; in a meta-analysis of 24 studies with 1,497 participants, 30.11% versus 10.43% in the control groups. No diagnosis, no treatment recommendation.

BK-Score Thin human evidence

Human evidence4
Mechanism6
Safety data7
Hype gap3
Track record of use8

The best supported is diabetic foot ulcer, and there for the six-week endpoint (Cochrane 2015: in 5 pooled studies with 205 participants, relative risk 2.35 after six weeks; no benefit any more after one year); in Germany, the therapy for this has also been covered by statutory health insurance on an outpatient basis since the G-BA decision of 2017. For the most frequently cited indication, carbon monoxide poisoning, the Cochrane analysis (6 studies, 1,361 patients) found no significant benefit. The longevity use rests on an Israeli study without a control group (35 participants, 60 sessions), whose telomere finding has not been independently confirmed, and on two small randomized trials by the same group with 63 older adults each, which showed improvements in cognition and maximal oxygen uptake – against doing nothing, not against sham treatment.

The score rates the state of knowledge, not the effect. “Safety data 9” means well studied – not harmless.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)

Frequently asked questions about hyperbaric oxygen therapy (HBOT)

Is the chamber in a wellness studio the same as the one in a hospital?

No. The UHMS defines clinical HBOT as treatment above 1.4 ATA with 100% oxygen and explicitly states that applications below 1.4 ATA are not HBOT for medical purposes, with the sole exception of acute altitude sickness. Soft chambers typically operate at 1.2 to 1.4 ATA with room air or a concentrator. Almost all studies that providers cite were run at 2.0 ATA or above.

How many sessions does that actually mean?

In the longevity studies, 60 sessions on five days a week over three months, each 90 minutes at 2 ATA. In the long COVID study, 40 daily sessions. That is a considerable investment of time and money, and shorter series were not tested in these studies. Anyone who books ten appointments does not have a slimmed-down version of the protocol but an untested one.

Is the claim about longer telomeres true?

It was measured in healthy people aged 64 and over: relative telomere length in several blood cell types increased by more than 20%, in B cells by up to 37.63%. This study had no control group, as the authors themselves write, and the finding has not been replicated by any independent group to this day. Telomere length in blood cells is, moreover, a surrogate marker and not proof that someone is aging more slowly.

Does HBOT help with long COVID?

There is a double-blind, sham-controlled randomized trial with 73 participants and 40 sessions in which cognition, energy, sleep, psychiatric symptoms and pain interference improved significantly compared with sham treatment, with effect sizes between about 0.46 and 0.74. It is the methodologically cleanest paper on HBOT beyond wound healing. At the same time, it is a single study from one group, and the number of participants is small.

How dangerous is it?

The most common side effect concerns the ears: in a systematic review of 18,284 patients, 15% otological events, and of the barotraumas 6.4% were severe. Seizures due to oxygen toxicity are rare, 43 in 188,335 sessions in a 20-year analysis, but there is one documented death afterwards. An untreated pneumothorax is an absolute contraindication; COPD and asthma are relative ones.

Isn’t HBOT proven for carbon monoxide poisoning?

That is the indication most often cited as established, but the Cochrane analysis of six randomized trials with 1,361 participants found no significant benefit over normobaric oxygen (odds ratio 0.78; 95% CI 0.54–1.12) with substantial heterogeneity. Two more recent meta-analyses find benefits in individual endpoints such as memory performance, but no consistent overall picture.

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Sources

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Information only, not medical advice and not a usage recommendation. If you have pre-existing conditions, and before making major changes, consult a doctor. Last updated: 2026-10-06.