therapies · education ·
Does Hyperbaric Oxygen Actually Work? The Answer Depends On The Pressure
One double-blind trial is genuinely strong. One measurement of what soft chambers deliver is genuinely awkward. Both belong in the same article.
There are two loud rooms in this conversation.
One sells miracle oxygen in a zip-up bag with soft proof. The other waves the whole idea away as something for scuba accidents.
Both are wrong, and the interesting part is that the same literature embarrasses each of them.
The trial that makes the strongest case
The HODFU study was randomized, single-centre, double-blinded and placebo-controlled, which is rare in this field. Ninety-four patients with Wagner grade 2 to 4 diabetic foot ulcers that had been open for more than three months (Löndahl et al., Diabetes Care, 2010).
The protocol was serious: 85 minutes a day, five days a week, for eight weeks. Forty sessions.
The control group is what makes this trial worth citing. They were not left alone. They were pressurised in the same chamber breathing hyperbaric air, so neither they nor the assessors knew who was getting the oxygen.
At one year:
- 52% healed in the hyperbaric oxygen group (25 of 48)
- 29% healed in the placebo group (12 of 42), P = 0.03
Among those who completed more than 35 sessions, the gap widened to 61% against 27% (P = 0.009).
The authors’ own framing is the one to keep: hyperbaric oxygen facilitates healing of chronic foot ulcers in selected patients, as an adjunctive treatment. Adjunctive. Selected. Those two words are doing real work.
Now the awkward measurement
Here is where the wellness version of this runs into trouble.
Researchers measured transcutaneous tissue oxygen in 130 consecutive chronic ulcer patients breathing 100% oxygen at two different pressures (Sack et al., Undersea and Hyperbaric Medicine, 2024).
- At 1.4 atmospheres: mean tissue oxygen 161 mmHg
- At 2 atmospheres: mean tissue oxygen 333 mmHg (p < 0.001)
Roughly half the dose. And soft-sided home chambers typically run at 1.3 atmospheres, below even the lower figure tested here, often on a concentrator rather than 100% oxygen.
The authors do not hedge their conclusion:
We have not found evidence supporting the claim that 1.4 ATA treatment can benefit a chronic ulcer patient.
Sack et al., Undersea and Hyperbaric Medicine, 2024
That sentence is inconvenient for a large industry, and it belongs in any honest article on the subject, including this one.
But soft pressure is not nothing either
Now the finding that embarrasses the other room.
Ten healthy adults were exposed to 1.27 atmospheres of ordinary room air, not oxygen, for 90 minutes a day, ten sessions over two weeks (MacLaughlin et al., Frontiers in Neurology, 2023).
Circulating stem progenitor cells rose roughly two-fold by the ninth exposure (p = 0.02), and roughly three-fold 72 hours after the final session (p = 0.008).
Ten people. Healthy volunteers. Biomarkers rather than outcomes. Grade it accordingly.
But it makes a point with teeth: the authors argue that studies using hyperbaric air as a placebo may have been comparing one dose against another rather than treatment against nothing. If that is right, some of the field’s negative results have been misread.
So what does “does it work” actually mean
It is never one question. It is four.
Which problem? Chronic diabetic foot ulcers have a double-blind trial. Most of the popular claims do not.
Which pressure, and what is in the tank? 1.3 atmospheres on a concentrator and 2 atmospheres on near-pure oxygen are not the same intervention wearing different clothes. The tissue oxygen differs about twofold.
How many sessions? Forty. Not four. The benefit in HODFU got clearer in people who did more than 35.
How honest was the control? This field is unusual in having a genuinely good sham, and the trials that used one are the ones worth weighing.
What we will and will not say
| Claim | Our line |
|---|---|
| Hyperbaric oxygen treats, cures or prevents disease | Never, not as a THS promise |
| HODFU found 52% against 29% healing at one year | Yes, with the double-blind design named |
| Tissue oxygen is about half at 1.4 ATA versus 2 ATA | Yes, and we quote the authors’ conclusion |
| Soft chambers are equivalent to clinical protocols | No. The measured dose says otherwise |
| Soft chambers do nothing at all | Also no. Room air at 1.27 ATA moved stem progenitor cells |
| Hyperbaric oxygen is an anti-ageing treatment | Not established. Biomarker papers exist; outcomes do not |
What a session is actually like
A course is forty sessions: 85 minutes of treatment inside a 95 minute total, five days a week for eight weeks in the trial above. That is closer to a course of physiotherapy than to an appointment, and it is better to know that going in than to find out in week three.
As for what people feel, one centre went back through 2,334 patients treated over four and a half years and counted every adverse event (Hadanny et al., Undersea and Hyperbaric Medicine, 2016). Measured per session the rate was 0.72%, and the great majority of it was one thing. Middle ear barotrauma is the common complaint, affecting 9.2% of patients but only 0.04% of sessions, while everything else tracked, from dizziness to anxiety to low blood sugar, came in between 0.5% and 1.5% of patients each.
That one issue is the same thing your ears do on a descending aircraft. Pressure changes on the outside of the eardrum and the pressure behind it has to equalise through a narrow tube, so if the tube does not open quickly enough you feel it. It has nothing to do with oxygen, it happens mostly in the early sessions, and swallowing, yawning and a gentle pinch-and-blow are usually all it takes. Women and children under 16 were more affected in that analysis, and anyone congested will have a harder time of it, which is why the descent rate matters and why a good operator talks you through equalising instead of pressurising the chamber and leaving you to work it out.
The authors of that safety analysis concluded that with strict operational protocols, pre-treatment evaluation and in-chamber monitoring, hyperbaric oxygen can be considered one of the safest medical treatments available today. The conditional is the part worth carrying: not that it is safe, but that it is safe when the protocols are followed, which is exactly what the questions below are for. A wider review makes the same point from another direction, noting that protocols still vary between institutions (Heyboer et al., Advances in Wound Care, 2017).
The thing to actually check before you pay anybody
There is an absolute contraindication: an untreated pneumothorax, a collapsed lung. Pressure changes can turn that into a life-threatening emergency on the way back up. Ear and sinus problems need screening too.
So three questions, in writing, to any clinic or any company selling a bag for your spare room:
- What pressure, in atmospheres absolute?
- What is the oxygen source, and roughly what concentration am I breathing?
- Who screens me for pneumothorax and ear and sinus risk before the first session?
An operator who cannot answer those plainly is not one to hand money to. An operator who can is telling you what dose you are actually buying, which is the entire question.
Where the design shows up
Oxygen is the one input the body cannot store and cannot wait for. Minutes without it and the argument is over.
What hyperbaric pressure does is unremarkable in principle: it dissolves more oxygen into the plasma, so tissue that has lost its blood supply can still receive some. It is not adding a capability. It is getting a delivery past a blockage, to repair machinery that was already there and already willing.
“For the life of the flesh is in the blood.” Leviticus 17:11, NASB
The verse carries the conviction. Ninety-four patients and a genuine placebo carry the number.
What to do this week
Nothing you have to buy.
If you are considering this, the useful move is the three questions above, asked before any deposit. If the answers are vague, that tells you what you needed to know.
And the unglamorous part: oxygen delivery answers to things you already control. Smoking narrows the vessels this is trying to push oxygen through. So does uncontrolled blood sugar. A chamber does not cancel either, and no trial has ever suggested it does.
Read this next: our own position on which chamber to own, stated as a position rather than dressed up as data: hard chamber or soft, and why range is the whole argument. For the evidence-grading method behind how we sorted these tiers, two of medicine’s top editors say you can’t believe much of it.
Sources
- Löndahl M, Katzman P, Nilsson A, Hammarlund C. “Hyperbaric oxygen therapy facilitates healing of chronic foot ulcers in patients with diabetes.” Diabetes Care, 2010;33(5):998-1003. https://pubmed.ncbi.nlm.nih.gov/20427683/
- Sack RA, Pikkel YY, Shemy OL, Ramon Y, Ullmann Y, Zeltzer AA. “Transcutaneous oximetry values in chronic ulcer patients during hyperbaric treatment at 1.4 ATA compared to 2 ATA.” Undersea and Hyperbaric Medicine, 2024;51(1):1-5. https://pubmed.ncbi.nlm.nih.gov/38615347/
- MacLaughlin KJ, Barton GP, Braun RK, et al. “Hyperbaric air mobilizes stem cells in humans; a new perspective on the hormetic dose curve.” Frontiers in Neurology, 2023;14:1192793. https://pubmed.ncbi.nlm.nih.gov/37409020/
- Hadanny A, Meir O, Bechor Y, Fishlev G, Bergan J, Efrati S. “The safety of hyperbaric oxygen treatment: retrospective analysis in 2,334 patients.” Undersea and Hyperbaric Medicine, 2016;43(2):113-122. https://pubmed.ncbi.nlm.nih.gov/27265988/
- Heyboer M, Sharma D, Santiago W, McCulloch N. “Hyperbaric Oxygen Therapy: Side Effects Defined and Quantified.” Advances in Wound Care, 2017;6(6):210-224. https://pubmed.ncbi.nlm.nih.gov/28616361/
Article metadata retrieved from PubMed. Photograph from Pexels. Scripture quoted from the New American Standard Bible.
Educational content from True Health Solutions. We do not diagnose or prescribe, and nothing here is a substitute for care from someone who knows your history. The body heals. We write about what supports that design.
Questions people ask
- Does hyperbaric oxygen work?
- For some things, at some pressures. In a double-blind trial of chronic diabetic foot ulcers, 52% healed within a year on hyperbaric oxygen against 29% on hyperbaric air placebo. For most of the popular claims, the evidence is thinner than the marketing.
- What is the difference between soft and hard chambers?
- Pressure, and therefore the oxygen dose reaching tissue. Measured in 130 chronic ulcer patients breathing 100% oxygen, tissue oxygen averaged 161 mmHg at 1.4 atmospheres against 333 mmHg at 2 atmospheres. Roughly half.
- So are soft chambers useless?
- Not biologically inert, but not equivalent either. The team who measured the tissue oxygen wrote that they found no evidence 1.4 ATA benefits a chronic ulcer patient. Separately, ten healthy volunteers at 1.27 ATA on plain room air showed stem progenitor cells roughly tripling. Something happens. Whether it helps a given problem is unsettled.
- How many sessions do the trials use?
- The foot ulcer trial used 40 sessions, 85 minutes a day, five days a week, for eight weeks. In the subgroup completing more than 35 sessions the gap widened to 61% against 27%. This is not a one-off appointment.
- What are the side effects?
- Across 2,334 patients at one centre the rate of adverse events per session was 0.72%, and most of it was one thing: middle ear barotrauma, affecting 9.2% of patients but only 0.04% of sessions. It is the same pressure-equalising problem as a descending aircraft, it clusters in the early sessions, and everything else tracked came in between 0.5% and 1.5% of patients.
- Who should not go in a chamber?
- An untreated pneumothorax, a collapsed lung, is an absolute contraindication. Pressure changes can turn it into an emergency. Ear and sinus problems also need screening. Any operator worth using will ask about these before taking your money.
