The man who spends millions each year trying to slow ageing has revealed he’s living with autoimmune gastritis – a chronic disease that his famously meticulous health regime couldn’t prevent. Here’s what the diagnosis means, what the condition does to the body, and why Johnson believes it could become his next scientific challenge
For years Bryan Johnson has become the poster boy for modern biohacking. Every meal weighed. Every biomarker tracked. More than 100 supplements a day. Millions of dollars spent attempting to slow biological ageing.
So when Johnson revealed this week that he’d been diagnosed with autoimmune gastritis – a chronic autoimmune condition in which the body’s immune system attacks the stomach lining – it came as a surprise to many followers. “My stomach is eating itself,” he wrote on Instagram, explaining that years of unexplained low ferritin levels had finally led to a diagnosis.
The irony isn’t that biohacking failed
It’s tempting to see the diagnosis as evidence that longevity medicine doesn’t work. But that’s probably the wrong conclusion.
Autoimmune gastritis isn’t caused by someone failing to eat enough vegetables or skipping the gym. It’s a complex autoimmune disease in which the immune system mistakenly attacks acid-producing cells in the stomach. Over time, that can reduce the body’s ability to absorb nutrients including iron and vitamin B12, leading to fatigue, anaemia and an increased long-term risk of stomach cancer.
Johnson’s body had been dropping clues
Johnson explained that he’d experienced persistently low ferritin – your body’s iron stores – for more than a decade. After ruling out bleeding and other obvious causes through colonoscopy and endoscopy, doctors found antibodies attacking his stomach lining, confirming autoimmune gastritis.
In many people, low iron might simply be treated with supplements. Johnson’s case illustrates why persistent abnormalities—even seemingly minor ones—deserve investigation rather than simply masking the symptoms.
A reminder that biology is complicated
Johnson has never claimed he could become immortal overnight. His philosophy has always been to measure relentlessly and intervene wherever science allows.
Ironically, that obsessive monitoring may actually have worked in his favour. Autoimmune gastritis often develops silently over many years before it’s discovered. Because Johnson tracks hundreds of biomarkers, the condition was identified before more serious complications developed.
His next experiment
Rather than accepting the diagnosis, Johnson says he intends to throw the same combination of AI, advanced sequencing and personalised medicine at autoimmune disease that he has applied to ageing.
He has already sequenced around one million immune cells and says his team will investigate whether emerging technologies could eventually do more than simply manage the disease. Current medical practice focuses on monitoring and treating deficiencies rather than curing autoimmune gastritis, so Johnson openly acknowledges this is experimental territory.
What can the rest of us learn?
You don’t need a multi-million-dollar longevity budget to take something useful from Johnson’s experience. If anything, it’s a reminder that even the healthiest lifestyle can’t eliminate every risk. Genetics and autoimmune disease remain powerful forces.
What good health can do is improve your odds, help detect problems earlier and put your body in the strongest possible position to respond when life throws up something unexpected.
Johnson himself ended his announcement with perhaps the least controversial advice he’s ever given: don’t wait until your health becomes the only thing that matters before paying attention to it.
