Bryan Johnson's 90-Day Hyperbaric Oxygen Experiment: Protocol, Setbacks, and Reported Biomarker Results
Bryan Johnson
Bryan Johnson says that for several years he has been testing longevity therapies to ask whether "we are the first generation who won't die." One therapy he had not tried was hyperbaric oxygen therapy (HBOT), which he notes is used by scuba divers, stroke patients, and elite athletes. He set out to test whether it is "an important therapy" or "some other overblown longevity therapy that doesn't deliver results." He measured his biomarkers before and after 60 sessions over 90 days. By the end, he called HBOT the most effective longevity therapy he has done so far. He also acknowledged that nobody yet knows how it should be continued.
The Protocol and the Measurement Plan
Johnson's plan was 60 sessions of 90 minutes each, completed within 90 days. That adds up to 5,400 minutes in the chamber. Before starting, he measured a wide set of biomarkers as a baseline. He planned to repeat the same measurements at the end and check whether each marker improved, worsened, or stayed the same. He framed this before-and-after comparison as the evidence for deciding whether the therapy is worthwhile.
He points out that HBOT may seem exotic but is available in many cities, much like sauna or cryotherapy. In his view, that accessibility is part of what would make a positive result exciting.
Installing a Chamber Instead of Driving to a Clinic
The first step was installing a chamber. Johnson reasoned that if it were at a local clinic 15 minutes away, he would never manage to spend 5,400 minutes there. The time cost would be too high. He needed the therapy built into his daily routine in a way that still let him work, so he had a chamber installed in his clinic and used it every day.
He walks through the startup sequence on camera:
- Turn on the power converter.
- Turn on the pressurization.
- Turn on the oxygen.
- Turn on the system.
The controls are inside the chamber, so he can start and end a session himself. He connects the mask to the 100% oxygen supply, closes the doors, and starts pressurization. The chamber reaches 2 ATA, which he describes as equivalent to about 10 meters, or 33 feet, below water.
How a Session Works and What He Hoped It Would Do
According to Johnson, the higher pressure allows the body to be saturated with pure oxygen. He says more oxygen means faster healing and better mitochondrial function, and possibly slower aging. His goals were longevity, performance, and possibly lengthening his telomeres.
He explains telomeres as the protective caps on the ends of chromosomes, like the tips of shoelaces. They gradually shorten and fray with age. That shortening is linked to cellular aging and many age-related diseases, and he calls it "the ticking of your biological clock."
Each session alternates two phases. He breathes pure oxygen for 20 minutes, then takes a 5-minute break, and the cycle repeats. The chamber air itself stays at 21% oxygen, the same as normal air, while he breathes 100% oxygen through the mask. He describes the cycle as moving between high oxygen and low oxygen.
The Research That Motivated the Experiment
Johnson cites several studies his team reviewed.
Telomeres and senescent cells. In one study of an older population, HBOT increased telomere length by up to 38% and reduced senescent cells by up to 37%. He describes senescent cells as cells that release pro-inflammatory cytokines, "basically bad things you don't want in your body." He calls these numbers massive by longevity standards.
Athletic performance. He says the literature showed performance gains without any change in training or diet:
- a 10–15% improvement in VO2 max and anaerobic threshold
- a 7–10% increase in grip strength
- a 9.2% improvement in Olympic triathlon time (he says "increase in … time")
Other areas. He also mentions promising findings for tissue health, skin health, and the microbiome. He summarizes HBOT as holding "the promise of whole body rejuvenation."
Early Doubts and an Oxygen Supply Problem
By day five, Johnson was worried. He had thousands of minutes left, saw no benefits yet, and wondered whether he could finish. He reassured himself that the studies show gains building up over time rather than appearing at the start.
There was also a technical problem early on. The original oxygen concentrator reached only about 92% oxygen, and the protocol required 100%. The chamber itself could reach two atmospheres, but pure oxygen was not yet available. The team solved this by sourcing medical-grade canisters of 100% oxygen and connecting them to the chamber.
What the Experience Is Actually Like
Johnson calls the first sessions "a unique experience" and lists several difficulties.
- Safety worries. Being in a highly pressurized chamber made him wonder what would happen if something went wrong. Living in California, he thought about earthquakes and how quickly he could get out. He says the fastest depressurization from two atmospheres takes around two minutes.
- Claustrophobia. Many of his friends could not even get inside the chamber.
- Breathing. The mask can feel restrictive, with some resistance when inhaling.
- Duration and boredom. Sessions are long, and with nothing to do "you're kind of left with your thoughts."
In his words, HBOT "really tries you" in all of these ways.
Day 30: Turning the Chamber into a Workspace
Around day 30, Johnson again doubted he could finish. He says he runs four companies, does multiple therapies each day, and produces content about his results.
The turning point came when he realized he could safely bring electronics into the chamber. Because the chamber air stays at 21% oxygen and only the mask delivers pure oxygen, electronics are safe inside. Once he could work during sessions, the therapy became a daily ritual he looked forward to. It gave him focused time for his most important work while the treatment ran.
Why Skin Was a Particular Interest
Johnson was especially curious about skin effects. He cites a study reporting:
- a 12.8% increase in collagen fiber density
- a 144% increase in elastic fiber length
- a drop in fiber fragmentation from 90% to 10%
- a 40.9% increase in blood vessel count
Based on this, he describes HBOT as potentially "the world's best whole body skin rejuvenation therapy," and says such results are very hard to achieve with other methods. He had a personal reason for interest too: his team had tried to fix sun damage from his childhood, with little success.
The Reported Results
Johnson admits the whole effort could have been for nothing after reshaping his life around it for 90 days. He concludes it was worth it. He reports that his biomarkers improved across his entire body after 60 sessions. He says it is "reasonable to say" HBOT is the most effective longevity therapy he has done. Instead of summarizing, he chose to go through the improved markers one by one.
Inflammation. His high-sensitivity CRP, a measure of inflammation across the whole body, was undetectable. He calls this "a wild result." He describes inflammation as often the biggest driver of disease and dysfunction, a process called "inflammaging." In his words, HBOT "took inflammation in my body to zero."
VEGF. He reports a 300% increase in VEGF, a signal that promotes blood vessel growth. He notes the body has over 60,000 miles of blood vessels. He wondered how much new vessel growth he gained but says he doesn't have that number.
Akkermansia. Before HBOT, the gut bacterium Akkermansia was undetectable in his tests. He had been taking an Akkermansia supplement for two months, and it was still undetectable. After HBOT, he reports a 1,000% increase. He links Akkermansia to gut barrier integrity and metabolic health. He attributes the change to the supplement and HBOT together improving his body's absorption.
A dementia marker. He cites a marker he names as "pal 127," which he describes as specific to Alzheimer's disease. It fell by 28.6%. He was already below the risk threshold of the reference range, but still called the drop "pretty dramatic."
Skin. He calls skin the most visually dramatic change. He had read about the collagen, elastin, and fragmentation findings. Seeing them in his own skin, he says, transformed its health across his whole body. Multispectral imaging of his UV skin damage showed improvement of more than 10%.
Telomeres in Detail
Johnson explains his telomere results carefully because of the interest they attract in the longevity community.
His baseline in March 2024 was 11.4 kb. After HBOT it was 11.7 kb, a 2.6% increase. He compares this with the study population aged 65 and older, which saw increases of up to 38%. He says it is unsurprising that an older group would improve much more, since he was very healthy to begin with.
For context, he says both 11.4 and 11.7 kb correspond to the telomere length of a 10-year-old. His gain was about 300 base pairs. Since people lose roughly 20–40 base pairs per year, he describes the gain as roughly equivalent to a decade of aging. He says he gives these details so viewers can see both what the study showed was possible and what he experienced.
The Unanswered Question: How Much, and How Often?
After finishing, Johnson faces the question of whether to keep going. He says he has spoken with several experts and "the truest answer is nobody really knows." Current thinking suggests 20 sessions every three months might be appropriate.
The aim of maintenance, as he describes it, is to keep signaling the body to produce stem cells, VEGF, and blood cells. The goal is to prime the body "just enough but not too much." From his Blueprint work, he has learned that "the dose is the poison, the dose is the longevity benefit." He says his team will experiment to find the right maintenance dose and share the results.
Advice for Viewers
For anyone interested in HBOT, Johnson stresses following a structured protocol. A common mistake, he says, is spacing sessions too far apart. They need to fall within a limited time window for the benefits to build up.
On cost, he estimates clinics charge "maybe in the range of a few hundred per session." He hopes that as HBOT becomes more popular, more centers will open and prices will fall. He also advises consulting a doctor first, since the right approach may depend on individual conditions.
A Plan to Certify Clinics
Johnson expects people to have trouble finding qualified HBOT providers with the expertise they need. His team is working on an initiative he calls "Blueprint Quantified" to certify clinics that take an evidence-based approach.
He describes a possible tiered certification, levels one, two, or three, and says the details may change. Certified clinics would follow a protocol: measure baseline markers, deliver the therapy, and then measure again. The patient would then get a verifiable answer to whether the therapy worked for their specific concern.
He believes this will improve health care and outcomes. The central open question from his own experiment, what maintenance dose to follow after the first 60 sessions, remains unresolved. He says his team will keep testing and report back.
For the past few years, I have been testing the world's best longevity therapies to pose the question, are we the first generation who won't die? But there's one therapy I haven't tried, which scuba divers, stroke patients, and elite athletes use, and it could be one of the most promising therapies I've ever done. It's called hyperbaric oxygen therapy. Now, this therapy may seem a bit exotic. It's actually more common than you think, like sauna or cryotherapy. It is available in many cities, which makes it all the more exciting if this works.
So my protocol is to complete 60 sessions in 90 days. I will be doing sessions of 90 minutes. So this is what I've decided to do. I'm going to measure myself extensively as a baseline to figure out where I'm at right now with my biomarkers. And then at the end of the 90 days, I'm going to measure the same markers again and see, did they improve, worsen, or stay the same? And that will give us evidence: is this an important therapy, or is this some other overblown longevity therapy that doesn't deliver results?
First step was installing a chamber. I knew if it was at some local clinic where it took a 15-minute drive to get there, I would never be able to spend the 5,400 minutes doing that. It would be too much time. I had to build it into my life routine where I could also work. So, I had it installed in my clinic where I could do it every single day. Let me show you how I do this.
First, turn on the power converter. All right. Next is to turn on the pressurization. Flip this guy. All right. System with power. Get the pressurization, and the oxygen is now on. Now, we're going to turn the system on. And the controls we have are internal. So, I can jump in there and start the session and end the session. So, I'll hook these guys up. This is where the 100% oxygen comes from. Flip the mask. And then once this is done, I'll close the doors and start the pressurization. And it will go to 2 ATA, which is equivalent to 10 m or 33 ft below water.
The increased pressure in the tank allows your body to be saturated with pure oxygen. More oxygen means faster healing, better mitochondrial function, and possibly slower aging. I'm using HBOT for a few objectives. One is for longevity, two is for performance, and three is to potentially elongate my telomeres. What are telomeres? Telomeres are the protective caps at the ends of our chromosomes, like the tips of your shoelaces. As we age, they gradually shorten and fray. This shortening is linked to cellular aging and a wide range of age-related diseases. It's the ticking of your biological clock, a really important variable in longevity.
Now, one study we referenced for this therapy was in an older population. HBOT was efficacious in increasing the length of telomeres by up to 38% and reducing senescent cells by up to 37%. Senescent cells emit what are called pro-inflammatory cytokines. They're basically bad things you don't want in your body. In the longevity world, these are massive numbers.
In looking at the data around HBOT, a few things we found really encouraging. It had increased athletic performance without changing training or diet. For example, there was a 10 to 15% improvement in both VO2 max and anaerobic threshold, a 7 to 10% increase in grip strength, and a 9.2% increase in Olympic triathlon time. There's also a lot of promise in improving tissue, skin health, and microbiome. HBOT has the promise of whole body rejuvenation.
20 minutes pure oxygen, a 5-minute break, and then 20 minutes pure oxygen, 5-minute break. So you're going from high O2 to low O2. Now, inside this chamber, oxygen remains at 21%, the same as our atmosphere. I'm breathing 100% oxygen through the mask.
Now, by day five I was beginning to worry. I had 5,400 minutes to spend in that chamber. I was only 5 days in. I wasn't seeing the benefits. I wondered, can I really pull this off? But the studies show that the gains accumulate over time, not in the beginning.
Now, as we got started, we ran into a major problem. We initially had an oxygen concentrator, but it was only reaching about 92% oxygen, and we needed 100%. So, while the chamber could get to two atmospheres and it was ready to go, we didn't yet have 100% pure oxygen. So, to solve that problem, we sourced 100% oxygen medical grade canisters that we then connected to the chamber.
When you first start doing HBOT, it definitely is a unique experience. One, you're in a highly pressurized chamber, and it makes you wonder, what if something goes wrong? I live in California. There are a lot of earthquakes, and I wondered, if there's an earthquake, if I had to do something fast, how fast can I move? And so the fastest depressurization time from two atmospheres is around 2 minutes. A lot of my friends couldn't even get inside the chamber. They're too claustrophobic. Also, when you put on the mask, sometimes it can feel a little restricting, where you breathe in and there's some resistance when you are doing the therapy. So there are problems there. HBOT really tries you from claustrophobia, breathing, duration of time, and also if you don't have anything to do, you're kind of left with your thoughts.
I have to confess, by day 30 I was again questioning, am I really going to pull this off? My days are incredibly busy. I'm running four different companies. I have various therapies throughout the day, and I'm producing content to share the results with the world. And I wondered, can I really see this thing through? I wasn't sure. This is what changed this for me. When I realized I could safely have electronics inside the chamber, I could then begin working. Inside the chamber is 21% oxygen, which is the same as the atmosphere. That's why I can safely bring electronics inside here. And then it became part of a daily ritual that I actually looked forward to every day, where I could work and focus on my most important things, and we're doing the therapy at the same time.
In looking at the evidence, I was really curious how HBOT might improve my skin. One study showed a 12.8% increase in collagen fiber density, a 144% increase in elastic fiber length, plus a reduction in fragmentation from 90% to 10%, and finally, a 40.9% increase in blood vessel count. What this therapy amounted to is the world's best whole body skin rejuvenation therapy. This is extremely hard to do with other methods. I know; we've looked at the evidence. It was also important because we have tried to fix the sun damage I incurred as a child, and we've had very little success.
This entire thing could all have been for nothing, and I had invested a lot of time. I had spent 90 days. I had shifted my entire life to accommodate this therapy. I sat in this little teeny tiny cube, 5,400 minutes, and it was worth it.
After completing 60 HBOT sessions, my biomarkers improved across my entire body. I think it's reasonable to say that HBOT is the most efficacious longevity therapy I've done since starting this endeavor. Now, I'm going to read to you from this long list of biomarkers the things that improved, because I think it's actually worth going through each item. Normally, I would just try to summarize in some succinct fashion, but actually I think this extended list is really worth your learning.
So, first let me start with inflammation. This is a marker called high sensitivity CRP. You're looking at systematic inflammation across the entire body. And I had no detectable levels of systematic inflammation in my body. That is a wild result. Inflammation is oftentimes the biggest culprit of problematic disease and dysfunction inside the body. It's called inflammaging. And I had nothing in my body. So HBOT took inflammation in my body to zero.
As to VEGF, this is a signal that boosts the growth of blood vessels. So, I had a 300% increase in VEGF, which is signaling the increase of this blood vessel growth. You may not realize, but you have over 60,000 miles of blood vessels in your body. I'm curious, how many miles of blood vessels did I lay down track for? I don't have that number, but really interesting to learn.
As to my gut health, my Akkermansia before HBOT was not detectable. Afterwards, it was a 1,000% increase. Now, Akkermansia is linked to gut barrier integrity and metabolic health. I have been taking an Akkermansia supplement for 2 months, and it was still undetectable even before HBOT. Then after HBOT, it increased by 1,000%. The combination of the supplement plus HBOT dramatically improved the absorption of my body.
Next, we looked at the dementia marker pal 127. So, this is a specific marker for Alzheimer's disease, and that declined by 28.6%. I was already below the reference range of someone indicating this was a risk for chronic disease, but still, to see it go down that much was pretty dramatic.
Now, in regards to skin health, I would say that was probably the most dramatic visual marker. I had read about the increased collagen production, the elastin, the reduced fragmentation from 90% to 10%. But then to see those variables take place in my own skin across my entire body, it just transformed the health of my skin across my body. We also used multispectral imaging to measure my UV skin damage, which improved by over 10% in the HBOT protocol.
Now, as it relates to telomeres, I'd like to explain a few details because I think it's worth you knowing. I had a baseline measurement in March of 2024, and my measurement was 11.4 kb. After HBOT, they measured at 11.7 kb. That's a 2.6% increase. Now, in the studies we looked at, people in this older population, 65 and older, experienced up to a 38% increase in telomere elongation. So, it's not surprising that that age group would have a significant improvement, whereas I'm very healthy to begin with. Now, to give you context on 11.4 and 11.7, that is the age equivalent of a 10-year-old. So my telomeres, which are a significant representation of biological age and health, are already at a 10-year-old level. In the gain I had, which was basically 300 base pairs from 11.4 to 11.7, what you have to consider is each of us loses between 20 and 40 base pairs each year. So I gained 300, which is roughly equivalent to a decade of aging.
I explain this detail to you because telomeres really are something that's very exciting in the longevity community. Therapies that can actually elongate them are very promising. And so I want to give you context of what the study showed was possible and then what I experienced myself.
Now that I've completed 60 sessions in 90 days, the question becomes, do I do more? I've spoken to several experts, and the truest answer is nobody really knows. Currently, the thought is 20 sessions every 3 months might be appropriate. What you're trying to do is to say, hey body, keep on producing the stem cells, keep on producing the VEGF, keep on producing blood cells. You're trying to prime the body just enough but not too much. I've learned this with Blueprint: the dose is the poison, the dose is the longevity benefit. So, as we experiment with the continuation of this protocol, trying to figure out the right maintenance dose, as always, we will share the results with you.
At this point, you may be pretty excited about HBOT. And if you are, I understand. I would be too. And what you want to do is follow a certain protocol. People oftentimes make the mistake where their sessions are spread out too far apart. They need to be within some kind of constrained time frame for the benefits to accumulate. But it can be expensive. I think clinics charge maybe in the range of a few hundred per session. So I hope that as HBOT increases in popularity, more centers open, systems become cheaper, and more people have greater accessibility.
Now, as always, before you do HBOT, make sure you consult with your doctor, as what you may do may be unique to your certain conditions.
Now, one thing I know everybody's going to experience is you're going to try to find an HBOT provider that qualifies and meets your needs. And sometimes you can't find all the expertise you need. So, we are working on this in building an endeavor called Blueprint Quantified. We want to certify clinics for taking an evidence-based approach in what they do. So, we'll say if you're going to offer HBOT, you can be certified one, two, or three. And this may change in time, but you're going to follow a protocol where you take a baseline measurement of markers, you do a given therapy, and then you measure again, so that when you go to the clinic, you have a verifiable outcome. Did it work? Did it not work for the thing you're trying to address? This is going to improve health care. It's going to improve outcomes. It will make you and everyone else a better person in life.
Article published