Hyperbaric & compression · graded by use, two uses
Hyperbaric Oxygen Therapy
2.0 ATA or higher, 100% oxygen by mask or hood.
Grade C: human trials exist, but they are small, mixed or not yet repeated. This is not a finding that it does not work. How to read a grade →
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How this letter has changedLatest: October 2026 · Downgraded.
The use rests on one randomized trial of 63 people (Hadanny et al., Aging, 2020; PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 32589613), and a search found no independent replication The same finding reproduced by a separate research group. A result seen once can be chance or bias; a replicated one is harder to explain away.. The C definition covers a single positive trial nobody has independently repeated. Applied the written grade definition in October 2026.PMID 32589613
Every change to a letter on this site is dated and published. The full evidence log →
Hyperbaric oxygen means breathing pure oxygen in a pressurized chamber. At full strength, one study of 63 healthy older adults found better scores on some thinking tests. No outside group has repeated it. Soft chambers at lower pressure, often sold for home use, were the fake treatment in that study, and they showed no benefit.
The C belongs to one of the two uses graded on this record. The other one carries its own letter.
As studied, and the trials
Hadanny et al. (Aging, 2020; PMID 32589613): 63 healthy adults over 64, 60 sessions at 2.0 ATA with 100 percent oxygen or no treatment for 3 months; global cognitive function improved, most in attention and processing speed. One trial, with no sham A fake version of a procedure or device used as the comparison, so participants cannot tell which one they received. arm and not repeated by an independent group: C.
As studied, and the trials
Read the grade that matches your goal. How EBL grades by use →
A letter describes the human evidence, not the product, the manufacturer, or the intervention's worth.
See the full evidence record →Graded on Cognition / vascular (2.0 ATA or higher, 100% oxygen).
Why this gradeGrade C, small or unreplicated trials. The reasoning, and what the grade does not cover.
Grade C at 2.0 ATA or higher with 100 percent oxygen, on cognitive measures in healthy older adults: one trial of 63 people (Hadanny et al., 2020; PMID 32589613), not repeated by an independent group. At 1.3 to 1.5 ATA on concentrator air the use is graded D: that was the sham condition, and it showed no benefit; a pediatric cerebral palsy trial is narrower in scope (Collet et al., 2001; PMID 11558483).
WHAT THIS GRADE DOES NOT COVERchambers by shell type, since a rigid shell does not settle pressure or gas; and clinical outcomes such as dementia, which no cited trial measured.
A grade describes the human evidence for a named use. It is not advice, and it is not a judgment on any individual prescription. How the letters are decided →
Each use, with its trials
This record carries a separate letter for each thing it has been measured on. The headline grade is the best of them, and it does not transfer to the others.
Hadanny et al. (Aging, 2020; PMID 32589613): 63 healthy adults over 64, 60 sessions at 2.0 ATA with 100 percent oxygen or no treatment for 3 months; global cognitive function improved, most in attention and processing speed. One trial, with no sham arm and not repeated by an independent group: C.
The evidence, in fullTwo papers, each linked to its PubMed record.
Hadanny et al. (Aging Albany NY, 2020; PMID 32589613): RCT Randomized controlled trial: people are assigned to the treatment or a comparison by chance, so the groups differ only in what they received. It is the design that can show cause and effect.: HBOT improved some cognitive measures in healthy older adults. Collet et al. (Lancet, 2001; PMID 11558483) is a pediatric cerebral-palsy RCT of narrower scope. Grade C: one randomized trial in 63 healthy older adults, not repeated by an independent group.
The primary clinical endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score. specific to the indication: wound size for non-healing wounds, neurological function scales for post-stroke or TBI, cognitive testing for longevity applications. Session count, pressure (ATA), oxygen concentration, and session duration at every treatment. The most-studied longevity protocol used 60 sessions at 2.0 ATA over 90 days.
Evidence notes: randomized trial
Endpoint graded: Cognition / vascular (2.0 ATA or higher, 100% oxygen) (functional)
Last reviewed: July 2026
Educational use only · Not medical advice · EBL grades published human evidence and does not recommend treatment. Stopping a prescription is a decision for your physician.
Primary evidenceTwo papers, each linked to its PubMed record.
Hadanny et al. (Aging Albany NY, 2020; PMID 32589613): RCT: HBOT improved some cognitive measures in healthy older adults. Collet et al. (Lancet, 2001; PMID 11558483) is a pediatric cerebral-palsy RCT of narrower scope. Grade C: one randomized trial in 63 healthy older adults, not repeated by an independent group.
Products carry no letter. The letter belongs to the therapy as the trials studied it, and no trial tested these products unless the entry says so. Listed alphabetically; payment does not affect order.
Acrylic monoplace chamber for whole-body administration of oxygen, Class II prescription device under 21 CFR 868.5470.
Reaches the studied pressure band on 100% oxygen. BRAND NOTE: BARA-MED was an Environmental Tectonics product until February 2020, when Perry Baromedical acquired ETC's hyperbaric division. Listings still describing it as an ETC chamber are naming the former owner.
Most-installed home HBOT unit in the US. Operates at 1.3 to 1.4 ATA. That is the pressure range used as the sham condition in the supporting trials, not the 2.0 ATA studied protocol.
Soft-shell chamber at 1.3 to 1.5 ATA; delivers the pressure that tested null, not the 2.0 ATA studied protocol.
Hard-shell aluminum chamber sold as a non-medical device for wellness centers and home use. Air-filled: oxygen is breathed through a mask from a concentrator, with no oxygen cylinders. Built for 2 ATA, with a software operating limit of 1.5 ATA.
SPEC RESOLVED September 2026. The manufacturer states the chambers are built for 2 ATA maximum working pressure and that the OxyLife I is marked and sold as a NON-MEDICAL DEVICE with a software limitation of 1.5 ATA. Both figures this record carried were right about different things: 2.0 is the build rating, 1.5 is the operating limit. 1.5 ATA is inside the band that tested null.
Monoplace chamber rated to 3.0 ATA, 100% oxygen. Class II prescription device under 21 CFR 868.5470. Built to ASME PVHO-1 Section VIII Division 1 and NFPA 99 Chapter 14.
Reaches and exceeds the studied 2.0 to 2.4 ATA band on 100% oxygen.
Monoplace acrylic chamber, 35.5 inch internal diameter, maximum 3.0 ATA (30.0 psig), configured as a 100% oxygen system. Built to ASME PVHO-1, NFPA-99 and 21 CFR Part 820. Prescription device.
This is the chamber the supporting evidence runs on. Published protocols and a current registered trial specify the Sechrist 3600 at 2.0 to 2.4 ATA with 100% oxygen. Pressure and gas both match the studied protocol, which is why fidelity is High rather than assumed from the shell.
Soft-shell home chamber. 1.3 ATA maximum. That is the pressure range used as the sham condition in the supporting trials, not the 2.0 ATA studied protocol.
Soft-shell chamber at 1.3 to 1.5 ATA; delivers the null-tested pressure, not the 2.0 ATA protocol.
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How EBL searched for the trials (1 search)
The search that was run, what it returned, and what was left out and why, so the absence of evidence can be checked as well as its presence.
("hyperbaric oxygen"[tiab]) AND (cognitive[tiab] OR cognition[tiab]) AND (aging[tiab] OR older[tiab] OR elderly[tiab]) AND randomized controlled trial[pt]Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →