Biohacker Bryan Johnson reveals autoimmune gastritis diagnosis: 'My stomach is eating itself'

Published 3 July 2026 · health

Bryan Johnson, the technology entrepreneur and anti-ageing advocate known for spending millions of dollars annually on health optimisation and anti-ageing interventions, has revealed that he

Bryan Johnson, the technology entrepreneur and anti-ageing advocate known for spending millions of dollars annually on health optimisation and anti-ageing interventions, has revealed that he has been diagnosed with autoimmune gastritis (AIG), a chronic autoimmune disorder in which the body's immune system attacks the stomach lining. Biohacker Bryan Johnson reveals autoimmune gastritis diagnosis in a lengthy post In a lengthy post shared on X, Johnson described his diagnosis as both a personal and scientific challenge, saying he plans to publicly document his attempts to better understand and potentially treat the condition. "Bad news #1: I have an autoimmune disease. My stomach is eating itself (sic)," Johnson wrote. He added: "Bad news #2: 2–5% of people have this, too. Likely more, because it hides (sic)." Johnson, 48, who has gained international attention through his longevity project Blueprint and his extensive experimentation with health monitoring and age-reversal therapies, said he was diagnosed with autoimmune gastritis in May after years of unexplained low iron stores and a history of autoimmune thyroid disease. "Good news: I'm going to try and solve it. Will share all (sic)," he wrote. According to Johnson, his medical history dates back to a diagnosis of hypothyroidism at the age of 21, for which he has long received hormone replacement therapy.

However, he said that for more than a decade, doctors were unable to determine why he persistently suffered from low ferritin levels despite dietary interventions and supplementation. "My hypothyroidism got diagnosed when I was 21 years old with a routine blood draw (sic)," Johnson wrote. "What I didn’t know was that something else was going on inside my body: my stomach had begun attacking itself (sic)." Johnson said his medical team revisited years of clinical data after he overhauled his healthcare programme earlier this year as part of what he described as the groundwork for his "Immortals Care" protocol, which he said costs around $1 million annually. The investigation involved a colonoscopy, upper endoscopy, blood biomarker analysis and multiple gastric biopsies. According to Johnson, tests revealed elevated anti-parietal cell antibodies, while biopsies confirmed early-stage autoimmune gastritis. "We now had a formal diagnosis. I have autoimmune gastritis AIG. My stomach is eating itself (sic)," he wrote. Autoimmune gastritis is a relatively uncommon but often underdiagnosed condition in which the immune system attacks cells in the stomach that produce acid and intrinsic factor, a protein necessary for vitamin B12 absorption.