Bryan Johnson Claims Alleged Disease Is Causing His 'Stomach to Eat Itself' After Anti-Ageing Blood Experiment

What began as Bryan Johnson's pursuit of longevity has become his latest health challenge. The tech entrepreneur, whose Blueprint anti-ageing project and 2023 blood plasma exchange drew worldwide attention, has revealed he was diagnosed with autoimmune gastritis, an incurable autoimmune condition that he described by saying: 'My stomach is eating itself.'

Johnson, 48, said he received the diagnosis in May after years of unexplained low ferritin levels that his medical team struggled to explain despite extensive testing. He used the phrase to describe his immune system attacking healthy cells in his stomach lining.

Medical experts have not linked Johnson's earlier blood plasma experiment to the disease, whose exact cause remains unknown.

Bryan Johnson's Autoimmune Gastritis Diagnosis

Johnson disclosed the diagnosis in a social media post, saying autoimmune gastritis causes irreversible damage to the stomach lining and that current medical care focuses on managing the condition rather than curing it. He added that he plans to investigate potential therapeutic approaches using advanced immune-cell testing.

Autoimmune gastritis occurs when the body's immune system mistakenly attacks healthy stomach-lining cells. The condition can reduce the production of stomach acid and intrinsic factor, increasing the risk of iron deficiency, vitamin B12 deficiency, anaemia and, over time, stomach cancer. Experts say it often develops gradually and may produce few noticeable symptoms during its early stages.

Johnson said years of persistently low ferritin levels eventually prompted further investigations that confirmed the diagnosis.

Blueprint and the Blood Plasma Experiment

Johnson became one of the best-known advocates of longevity science through Blueprint, a programme combining strict nutrition, exercise, sleep optimisation, biomarker testing and experimental interventions designed to slow biological ageing.

One of Blueprint's most publicised experiments came in 2023, when Johnson underwent a blood plasma exchange with his teenage son, Talmage, to explore whether younger blood components could influence biological ageing. He later said the procedure produced no measurable anti-ageing benefits and discontinued the experiment.

Researchers cited by Northeastern Global News said autoimmune gastritis has no established link to plasma exchange. They said the condition is generally associated with autoimmune processes whose precise cause remains under investigation, with genetic and environmental factors believed to contribute.

Experts on the Limits of Health Tracking

Johnson's diagnosis has drawn attention from medical experts because it illustrates the current limits of personalised health monitoring. Ram Hariharan, director of programmes for the College of Engineering at Northeastern University's Seattle campus, described Johnson as 'arguably the most measured human alive,' yet said even extensive biological data cannot always detect diseases before irreversible damage has begun.

Immunologist Emeka Okeke said the exact cause of most autoimmune diseases remains unknown, while Dr Gian Corrado noted that such conditions are relatively common and can affect healthy, physically active people despite regular medical monitoring.

What's Next For Bryan Johnson

Johnson said he plans to continue analysing the immune cells attacking his stomach lining in the hope of identifying future treatment options and improving scientific understanding of autoimmune gastritis.

Although there is currently no cure for the condition, he said he intends to continue sharing his progress publicly, writing: 'I'm going to try and solve it. Will share all.'