Celebrity “biohacker” Bryan Johnson, whose efforts to slow aging were chronicled in the 2025 Netflix documentary “Don’t Die: The Man Who Wants to Live Forever,” revealed Tuesday that he has a new autoimmune disease — and wrote, “My stomach is eating itself.”
“It is true,” said Johnson in a video published on Instagram. “My stomach is eating itself, and here is why that makes me excited. For context, I was diagnosed with autoimmune thyroid disease at age 21. This is decades before I started my protocol.”
Johnson has been a huge proponent of the “Make America Healthy Again” mantra and is a veritable poster boy for burgeoning longevity culture. The 48-year-old has even used blood plasma transfusions from his own teenage son in hopes of reducing his biological age.
A supporter of President Donald Trump who has pledged his support for Health and Human Services Secretary Robert F. Kennedy Jr. to make America “the healthiest, most vibrant” nation on earth, Johnson said he’s “excited” about his latest diagnosis.
“Autoimmune gastritis affects millions of people around the world, and it currently has no cure,” he said in the video Tuesday. “We are going to try to solve that. A few days ago, I had a massive blood draw. We are sequencing 1 million of my immune cells.”
He continued, “We’re doing this because you have trillions of immune cells in your body that operate as soldiers. Each one of these immune cells, or soldiers, carries a specific key that is designed to kill a specific threat — like a virus or bacteria.”
Johnson said identifying these “rogue soldiers” through this sequencing process could help him and his team “design specific solutions” to prevent the cells from spreading, and that he would make the findings “reproducible” to help “millions of people” affected by the disease.
Autoimmune gastritis can lead to ulcers and an increased risk of stomach cancer, according to the Mayo Clinic. Symptoms include burning pain in the upper belly, as well as nausea, vomiting and an abnormal feeling of fullness in the upper abdomen after eating.
The incurable condition occurs when the immune system attacks the lining of the stomach, per the Cleveland Clinic. Johnson on Tuesday linked autoimmune gastritis, which affects up to 2% of the U.S. population, to his hypothyroidism diagnosis at 21.
“I’m 48 now, so this has been part of my body for 27 years,” Johnson wrote in the caption of his social media post. “What most people don’t realize is the thyroid and the stomach are closely linked in autoimmunity. When one is affected, the other often follows.”
He continued, “There’s even a clinical name for it (thyrogastric syndrome) first described in the 1960s. A recent bidirectional endoscopy revealed autoimmune gastritis. It’s the same underlying autoimmune tendency I’ve lived with since 2021, now showing up in my stomach.”
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Johnson has self-admittedly spent millions of dollars on his quest for longevity, with ostensible solutions to slow his aging spanning from supplements to artificial intelligence, and has been both praised and ridiculed on social media for the ongoing endeavor.
The former Mormon and biotech entrepreneur has largely stayed out of politics, save for congratulating Trump and praising Kennedy, but urged Trump and Tesla CEO Elon Musk in 2025 to get a “few nights’ sleep” in order to resolve their public feud at the time.
Johnson revealed last year that he is determined to live longer than a century and said in the Netflix documentary, “I really want to have multiple lifetimes with my son. One hundred years is not going to be enough.”