Bryan Johnson on His Autoimmune Gastritis Diagnosis and the Plan to Cure It

How the Diagnosis Came About

The diagnosis came the previous month, after what Johnson describes as a bidirectional endoscopy: a colonoscopy combined with a scope through the throat, allowing doctors to examine his entire intestinal tract.

Johnson connects the finding to something from his early twenties. At 21 he was diagnosed with hypothyroidism and began taking hormones to regulate his thyroid. He explains that the thyroid and the stomach "pair really well together in immunology," so a problem with one sometimes comes with a problem with the other. He notes that there is a clinical name for this pairing, though he doesn't give it. Until now, he says, he had no idea anything was happening in his stomach.

What the Condition Does

Johnson describes the immune system as trillions of soldiers. Each immune cell carries a specific "key" designed to destroy a specific target, such as a virus or a bacterium. In his case, some of these cells "went rogue." Instead of attacking foreign threats, they began attacking his own stomach.

According to Johnson, this changes his stomach acidity and prevents him from processing certain nutrients. Iron is his main example: whether it comes from food or supplements, he can't absorb it. He says this leads to nutritional deficiencies and anemia, and can also create a risk of cancer.

Why Years of Measurement Missed It

Johnson addresses a question he says people often ask: given how much he has measured himself over the past few years, how could he have missed this? He calls it "a really hard one" and says the context is relevant to everyone watching.

Looking back, he says, he can now put the puzzle together. He has had low iron and low ferritin for 11 years. He says it is common for doctors to see this, note that other markers such as hemoglobin and hematocrit are normal, conclude the patient isn't anemic, and move on. His advice is that low iron is something "you really want to look into."

Earlier this year, Johnson rebuilt his medical care team, and the new team agreed to take a fresh look at everything. When they asked about his low iron, he told them he had been fighting it for a long time. He had eaten meat, taken supplements, tried every form of iron, and experimented with different times of day and with sequencing iron alongside other supplements. None of it raised his ferritin.

One doctor said this raised alarm bells. In the doctor's view, a failure to raise iron like that typically points to either a bleeding polyp in the colon causing blood loss, or some form of cancer. The team scheduled a colonoscopy immediately.

A Clean Colon and a Hidden Disease

The colonoscopy looked good. The doctor told Johnson his colon looked great visually. Johnson asked for a percentile ranking among all men, and the doctor put him at the 95th percentile, calling it "clean."

Johnson says this is exactly where the disease hides. A doctor can inspect the tract and still not identify the autoimmune condition. His doctors had anticipated this and took biopsies from several places in his stomach, so that any problem invisible to the eye would show up in the tissue samples. The biopsy results revealed the condition.

Johnson describes two barriers to detection. First, low iron isn't treated as seriously as it should be, even though it should prompt a colonoscopy. Second, even the colonoscopy didn't find the problem; only the biopsy did. Combined with his hypothyroidism diagnosis at 21, he says this completes the picture. He believes he may have had the condition for potentially more than 20 years, slowly eroding his stomach.

Why He Feels Energized

Johnson acknowledges that nobody wants a diagnosis, but says he feels energized and even excited by this one. He would much rather know now than learn later, when the condition is already causing stomach cancer. Knowing early, he says, lets you act early.

He contrasts this with how he sees the standard of care for conditions like this: an apology followed by managing the disease as well as possible. In his view, that approach concedes to the disease, whether or not it is fatal. With new AI and biotech tools, he argues, "we don't have to concede anymore." His first thought on hearing the diagnosis, he says, was that "we're going to solve it."

He is clear that this is an open challenge. The condition has never been cured and there is no known cure. He calls it "a really good challenge" for himself and his team.

The Plan: Identifying the Rogue Immune Cells

Johnson outlines the steps his team has taken so far and what comes next. After a large blood draw, they sequenced one million of his immune cells, examining each cell individually. He calls it amazing that this technology exists. For each cell, the team reads its "key," essentially asking, "Who are you?"

The next step is a second biopsy, which means he will have to go under again. It will be a live biopsy of his stomach. The team plans to take those stomach cells and match them against the blood sequencing data to identify which immune cells are the rogue ones attacking his stomach. Once they have those signatures, Johnson says, they can design solutions to stop the internal attacks. He does not describe what those solutions will be. The work is at the planning and data-gathering stage.

Public Reaction and Irony

Johnson says the global response has been "a lot of fun." Many people have expressed concern about his diagnosis, which he says he appreciates. Others are delighted by the irony that "the don't die guy" has been diagnosed with an incurable disease. He says he welcomes all of it. He notes that he was the first to say he would probably die of something incredibly ironic, calls that his fate, and says he has made peace with it.

From Fine-Tuning to Fighting Disease

Johnson closes by saying that he and his team feel "fired up" and want this task. He frames it as a shift in focus. The past few years were about fine-tuning the body through nutrition, exercise, and various protocols. The question now is how to take on the diseases that create mortality risk and actually solve them. Whether his team can cure a condition that has never been cured remains, by his own account, an open challenge.