A Self‑Experiment Like No Other
If you’re the kind of person who installs gadgets at home to test the latest wellness trends, you’d get along with Bryan Johnson. The billionaire founder of Braintree/Venmo is on a quest to slow down ageing—he calls it the “Blueprint”. In early 2025 he decided to spend 5,400 minutes (that’s 90 minutes a day, five days a week) inside a hyperbaric oxygen chamber. This therapy involves breathing nearly pure oxygen under pressure, and he hoped it would boost his health.
What He Tested
Before and after his 90‑day stint, Johnson checked a long list of biological markers:
Inflammation markers – blood tests looked for signs of chronic inflammation. After the experiment, he said the tests showed no detectable levels of inflammation
Brain aging biomarker – one blood marker linked to cognitive decline reportedly dropped by 28.6 %
Telomere length – these protective DNA caps on chromosomes often shorten with age. Johnson claimed they got longer after the sessions
Gut microbiome – he ran sequencing tests on his gut bacteria and said diversity improved dramatically
Skin health – he used imaging and skin scans; after the three months he said his skin looked much younger, with fewer UV spots
Did It Work?
By his own account, Johnson was thrilled. “This may be the most efficacious whole‑body rejuvenation therapy I’ve ever done,” he wrote. He shared charts and numbers online and sounded convinced that breathing all that extra oxygen made a huge difference.
Scientists, however, are more cautious. The most relevant published evidence comes from a 2020 clinical trial that gave 60 hyperbaric sessions to 35 healthy adults aged 64 or older. Their telomere length increased by 20–38% and senescent cell counts dropped by 11–37%. It’s a promising hint that pressurized oxygen can influence aging markers—but it’s also a small study without a control group. Johnson’s single‑person adventure is even more anecdotal.
The Bottom Line
It’s hard not to be fascinated by Bryan Johnson’s oxygen marathon. He sat in a sealed chamber, got his blood drawn and his skin scanned, then told the world about his results. While his enthusiasm is infectious, it’s important to remember that one man’s story does not prove a therapy’s effectiveness. Hyperbaric oxygen therapy is being studied, and there are small trials hinting at benefits, but we’re a long way from calling it a magic youth pill.
Until then, enjoy the story, stay curious about the science, and (as always) talk to your doctor before diving into pressurized wellness experiments.
Watch his YouTube video here: