Bryan Johnson, the billionaire entrepreneur and biohacker known for his ambitious anti-aging experiments, has revealed that he has been diagnosed with autoimmune gastritis, a rare chronic condition in which the immune system attacks the stomach lining.
Johnson shared the news with his 1.5 million followers on X, saying doctors discovered the condition while investigating years of unexplained low iron levels. The 48-year-old said his stomach had been “attacking itself” without causing noticeable symptoms for years.
According to Johnson, the autoimmune process may have started much earlier in life when he followed an unhealthy lifestyle that included sugary foods, soft drinks, fast food, stress, and weight gain. He also said medication for hypothyroidism, which he has taken since he was 21, may have masked the condition and delayed its diagnosis.
Doctors began investigating after Johnson continued to record low ferritin levels, a protein that stores iron in the body. A colonoscopy ruled out hidden bleeding, bowel cancer, and other gastrointestinal problems. His medical team then performed an upper endoscopy, specialized blood tests, and multiple stomach biopsies.
Although the endoscopy appeared normal, the biopsies confirmed early-stage autoimmune gastritis. Blood tests also showed elevated anti-parietal cell antibodies, indicating that his immune system was attacking the acid-producing cells in his stomach. Johnson said the disease was detected early enough to prevent more serious damage, adding that his iron deficiency has now been corrected.
Autoimmune gastritis is considered a lifelong condition that can reduce the body’s ability to absorb nutrients such as iron and vitamin B12. If left untreated, it may lead to anemia and increase the risk of stomach cancer. Treatment usually focuses on managing symptoms, correcting nutritional deficiencies, and regular medical monitoring.
Bryan Johnson said he plans to continue exploring new treatment options, including experimental therapies based on artificial intelligence-designed antibodies and synthetic proteins. He acknowledged that these approaches remain investigational and are not part of standard medical care.
The announcement has also sparked debate among medical experts. Some specialists say there is no evidence linking Johnson’s childhood diet directly to the disease, noting that autoimmune gastritis is influenced by multiple genetic and immune-related factors.
Johnson became internationally known through his multimillion-dollar “Blueprint” longevity program, which includes strict nutrition, extensive health testing, daily supplements, and advanced medical monitoring aimed at slowing aging. Despite his latest diagnosis, he says he remains committed to sharing his health journey publicly and believes future advances in science could improve treatment for autoimmune diseases that are currently considered incurable.