EXCLUSIVE: Biohacker Bryan Johnson Reveals Autoimmune Disease Diagnosis — After Trying to 'Live Forever'

The condition affects an estimated two to five percent of people, although Johnson said the true figure is likely higher because it frequently goes undetected.

His diagnosis followed months of extensive medical investigations carried out as part of his "Immortals Care" longevity program, which aims to extend human life through intensive monitoring and experimental therapies.

A source said: "People could not ignore the irony of this. Bryan has built his public image around living forever, so many immediately joked that reality had caught up with him. The comments have been brutal and sent directly to him on X, but Bryan is determined to keep searching for answers."

Another insider added: "His supporters see this as another challenge to solve, while critics say it shows nobody is immune to disease, regardless of wealth or technology."

In a lengthy post, Johnson described the long path to receiving the diagnosis and reflected on how his health changed over the years.

He said as a child he regularly ate fast food and sugary snacks before adopting healthier habits in his 20s. After becoming a father and focusing on building his business, however, he said his health deteriorated.

Johnson admitted: "Within a few years, I'd fallen into a deep, chronic depression. Somewhere in that timeline, my body began developing an autoimmune process affecting my thyroid and then my stomach lining."

The millionaire also explained he was diagnosed with hypothyroidism at 21 and had successfully managed the condition with conventional treatment for nearly three decades.

But persistent low ferritin levels remained unexplained despite repeated attempts to raise his iron stores.

Only in May did doctors identify autoimmune gastritis after Johnson replaced his medical team and underwent a series of detailed examinations.

Tests included a colonoscopy, which found no evidence of cancer, followed by a bi-directional endoscopy, blood biomarker analysis, and a stomach biopsy. Elevated anti-parietal-cell antibodies and changes to the stomach lining confirmed the diagnosis.

Johnson said: "I'm unsure how long I've had it. AIG causes irreversible damage – nutritional deficiency, anemia, and over a long horizon, elevated cancer risk."

Despite acknowledging there is currently no approved cure, Johnson said he refuses to accept that the disease cannot eventually be treated.

His team plans ongoing monitoring of iron levels and other biological markers while exploring experimental approaches, including immune-system protein targeting, rebuilding regulatory T-cells, and engineered cell therapies.

Johnson said: "In the age of AI, multiomics, and custom-built DNA, proteins, and cells, no condition should be presumed incurable simply because no one has yet tried to cure it with today's stack."

Johnson founded the payment company Braintree, which was acquired by PayPal for $800million in 2013.

Since then, he has become one of the world's best-known biohackers, investing millions of dollars in ambitious longevity experiments designed to slow aging and extend human lifespan.