Biohacker Bryan Johnson reveals he has incurable disease: ‘My stomach is eating itself’

Bryan Johnson, the 48-year-old technology entrepreneur widely known for his intensive, multi-million dollar longevity project, has disclosed that he has been diagnosed with autoimmune gastritis (AIG). The condition, which Johnson characterized in a post on social media as his “stomach eating itself,” is a chronic autoimmune disorder where the immune system attacks the parietal cells of the stomach lining. These cells are responsible for the production of stomach acid and intrinsic factor, the latter of which is a protein critical for the absorption of vitamin B12.

Johnson, who has gained international attention for his systematic approach to age-reversal and health optimization, revealed that he received the diagnosis in May. The discovery followed a lengthy period of unexplained health markers that persisted despite his highly regimented lifestyle. According to Johnson, he had struggled with low ferritin levels for 11 years, despite consistent efforts to raise them through dietary interventions and supplementation. Because his hemoglobin and hematocrit levels remained within normal ranges, he noted that the underlying issue was repeatedly overlooked by medical practitioners.

The path to diagnosis involved an exhaustive series of medical investigations, including a colonoscopy, a bi-directional endoscopy, and blood biomarker analysis. While the colonoscopy returned no evidence of cancer, further testing revealed elevated levels of anti-parietal cell antibodies. Final confirmation was provided by gastric biopsies, which identified early-stage weakening and atrophy of the stomach lining. Johnson’s medical history includes a diagnosis of hypothyroidism at age 21, for which he has long utilized hormone replacement therapy. Medical experts acknowledge a connection between autoimmune thyroid disease and gastritis, a combination sometimes referred to as thyrogastric syndrome.

AIG is estimated to affect between 2% and 5% of the population, though experts suggest the actual prevalence may be higher as the condition often progresses silently without obvious digestive symptoms. Left unmanaged, the disorder can lead to nutritional deficiencies, anemia, and, over a long period, an increased risk of gastric cancers and neuroendocrine tumors. Johnson, who previously experienced weight gain and chronic depression during his career, noted that his childhood diet of fast food and sugary beverages may have been an early factor, alongside years of stress.

The biohacker has already begun addressing the condition through a 1,000 mg intravenous iron infusion to correct his deficiency. However, he expressed dissatisfaction with the standard medical consensus, which he says treats the disease as something to be managed rather than resolved. Johnson intends to continue his pursuit of a more definitive solution, outlining a strategy that involves routine monitoring of biomarkers such as B12, gastrin, and chromogranin A, as well as repeat biopsies and exploratory therapeutic approaches. He has invited specialists working on antigen-specific tolerance, regulatory T cells, and CAAR-T for organ-specific autoimmunity to contact him.

Johnson’s disclosure serves as a broader call for proactive health monitoring. He argued that the absence of symptoms is not proof of health and that individuals should be more diligent about investigating persistent, subtle abnormalities like low ferritin, even when more common diagnostic markers appear normal. As he continues to document his journey, Johnson plans to share findings from his upcoming experimental interventions, aiming to challenge the current limits of clinical care for autoimmune conditions.