Longevity Digest — June 28–July 5, 2026

This week's longevity digest is less about a single protocol and more about where evidence stops. Bryan Johnson disclosed an autoimmune gastritis diagnosis with anti-parietal cell antibodies about 5 times the normal upper limit and biopsy-confirmed early atrophy; Peter Attia published a trial-heavy critique of metformin as a broad anticancer drug; David Sinclair promoted ER-100 and chemical reprogramming while outside criticism of longevity hype sharpened; Rhonda Patrick kept the actionable lane narrower with sleep, training, heat, and cardiorespiratory-fitness guidance. 1 2 3 4 5

The practical split is clear. Sleep timing, training fuel, hot yoga as an adjunct for depression care, and cardiorespiratory fitness are specific enough to evaluate. CAR-T for autoimmune gastritis, chemical reprogramming pills, broad metformin-for-aging claims, and single-person biomarker experiments are not ready-made protocols.

Bryan Johnson, founder of Blueprint and Immortals, made the week's largest personal disclosure on June 30: he said he had autoimmune gastritis, a condition in which the immune system attacks the stomach's acid-producing parietal cells. 1 Johnson said the case was found in May 2026, after years of low ferritin without anemia, and he reported anti-parietal cell antibodies of 103 Units/mL against a normal upper limit of 20 Units/mL. 1 He said upper endoscopy with 5 biopsies confirmed early atrophy limited to the acid-secreting mucosal layer, while colonoscopy showed a healthy colon. 1

Johnson's current treatment tier is comparatively conservative: zinc-carnosine and gastric-acid replacement with betaine HCl plus pepsin. 1 His later tiers move quickly into research territory, including JAK/STAT, GSK-3, IL-17, netazepide, induced regulatory T cells, CAR-T or CAAR-T, AI-designed antibodies, and synthetic proteins. 1 Johnson explicitly said there is no approved cure for autoimmune gastritis and described tiers 2 through 4 as investigational or preclinical rather than established care. 1

The next step is measurement. On July 3, Johnson said he had a large blood draw and planned to sequence 1 million immune cells to identify the "renegade" clones attacking his stomach lining. 6 He listed more than 50 tests, including ferritin, intrinsic factor antibodies, gastrin, chromogranin A, T/B/NK lymphocytes, TNF-alpha, IL-6, HLA typing, oxidized LDL, vitamin D, B12, methylmalonic acid, HbA1c, GlycA, CRP, NT-proBNP, p-tau217, NfL, and GFAP. 6

Johnson also pushed back against online claims that meat, sunlight, or his current diet caused the autoimmune gastritis. 12 He said he had maintained high vitamin D for years, had tried multiple oral iron forms without success, and had autoimmune thyroid disease starting at age 21, when he regularly ate red meat and spent hours outdoors daily. 12 His line was blunt: "Trying to cure a decades old, genetically driven, antigen specific immune failure by switching to a meat diet or getting sunlight is like trying to fix a corrupted line of software code by altering the temperature of the room." 12

Two lower-priority Johnson items still matter for the health frame. On July 2, Johnson cited a new npj Aging review reporting that cancer patients have a 25-35% lower Alzheimer's disease risk and Alzheimer's patients have about half the cancer risk, which the paper framed as a cancer-Alzheimer's disease paradox. 13 14 On July 5, Johnson responded to criticism that he is "trying not to die" by arguing that modern culture uses indulgence as a way to manage death anxiety. 15 The first item is research-adjacent; the second is philosophy, not protocol.

Peter Attia, physician and host of The Drive, published Podcast #398, AMA #86, on June 29. 7 The 54-minute subscriber AMA focused on GLP-1 receptor agonists and muscle loss, including semaglutide, tirzepatide, and retatrutide. 7 The free preview says Attia first used liraglutide clinically in 2014, saw semaglutide as a "step function change" around the fourth quarter of 2020, and now argues that DEXA-measured lean mass can mislead during GLP-1 treatment. 7

The actionable quote is narrow enough to use: "When patients are counseled thoroughly on how to consume protein [in the right amount] and how to properly engage in resistance training, we're seeing very little lean mass lost." 7 The detailed protein targets, resistance-training plans, retatrutide data, and gray-market warnings were behind the paywall, so the free material does not support specific gram targets or training prescriptions. 7

Attia's July 4 metformin article is more definitive. Michael Rae, Nicholas Nelson, and Attia reviewed MAST, a phase 3 randomized, double-blind, placebo-controlled trial across 12 Canadian cancer centers in 408 nondiabetic men with low-risk prostate cancer under active surveillance. 2 MAST found no significant progression-free survival benefit for metformin 850 mg twice daily versus placebo, with HR 1.09, 95% CI 0.79-1.52, and p=0.59 over a median 3-year follow-up. 2

The broader evidence also weakened the broad anticancer story. A 2022 meta-analysis of 22 randomized controlled trials with 5,943 participants found no effect on progression-free survival, with HR 0.97, or overall survival, with HR 0.98. 2 A 2024 meta-analysis of 27 randomized controlled trials with more than 20,000 people found no preventive effect on new cancer incidence, with RR 1.07. 2

There are exceptions, but Attia's conclusion is that they require precision, not broader use. A colorectal-polyp trial in 151 nondiabetic patients found metformin 250 mg reduced new adenoma risk by 40%, with RR 0.60 and 95% CI 0.39-0.92; a Chinese randomized trial in 272 high-risk patients reported adenoma recurrence falling from about 49% to about 30% with metformin. 2 Attia wrote that these exceptions "should motivate better trials, not broader use." 2

That puts Attia in tension with parts of the longevity-drug culture. Sinclair said this week that he still takes extended-release metformin 1 g, alternating with berberine. 3 Attia's article does not rule out every targeted metformin use, but it rejects the loose geroprotective frame.

David Sinclair, Harvard Medical School genetics professor and co-founder of Life Biosciences, returned with a July 3 appearance on The James Altucher Show. 3 He confirmed that the first glaucoma patient in the ER-100 phase 1 trial had been treated, matching Life Biosciences' June 9 press release. 3 8 ER-100 uses three Yamanaka factors, OSK, delivered by AAV2 directly into the eye, with doxycycline acting as a safety switch for gene expression. 3

Sinclair said the treatment may require 4-8 weeks to restore vision and could have durable effects, and he said accelerated approval could be possible "in the next few years" if FDA is satisfied with results. 3 Those are expectations, not reported clinical outcomes. The public materials do not provide ER-100 safety data, efficacy data, cohort size, durability results, or responder rates from treated humans. 3

Sinclair also said his lab is working on a chemical reprogramming "pill," said mouse work had shown skin rejuvenation and faster wound healing, and said, "We hope to dose our first human in 2026 if everything goes well." 3 The phrase "if everything goes well" matters. The claim is a development target, not a validated oral age-reversal therapy.

Sinclair's supplement update also changed in a limited way. He said he stopped regular taurine because later papers questioned its effect, started trying nattokinase, and continued NMN, extended-release metformin 1 g, and resveratrol. 3 He also said there is no evidence, positive or negative, for NAD injections, while oral NMN has more rigorous evidence. 3 This is not enough to specify nattokinase dosing or recommend it for artery "cleaning."

The week also brought outside pressure. On June 29, The New Yorker published Dhruv Khullar's essay reviewing Saul Justin Newman's Morbid and Ezekiel J. Emanuel's Eat Your Ice Cream, and the piece named Sinclair as one example in the critique of modern longevity science. 4 Khullar cited Sinclair's past description of resveratrol as "as close to a miraculous molecule as you can find" and noted that GSK later abandoned the compound after acquiring the related startup. 4 The essay did not include a response from Sinclair. 4

Two tracking items stay unresolved. Sinclair did not mention SL-100 in the 49-minute Altucher interview, more than 4 weeks after the initial public claim. 3 His previously mentioned Nature sirtuin paper also did not appear in the Altucher interview or the UNIC Athens coverage. 3 16

Dr. Rhonda Patrick, biomedical scientist and founder of FoundMyFitness, posted a fasted-training discussion on July 2 based on her March 30 appearance on The Diary of a CEO. 9 17 Her main rule was subjective but practical: "First and foremost, how do you feel when you exercise fasted? If you feel terrible, that's a sign." 17

Patrick distinguished short sessions from long ones. She wrote that "a 30-minute run or lift is very different from a 2-hour run or lift," and said long sessions may require fuel. 9 She also said 30-minute fasted cardio may improve mitochondrial adaptation, but women in sustained calorie deficits with high training loads may disrupt follicle-stimulating hormone and luteinizing hormone enough to cause amenorrhea. 9

Her June 30 sleep checklist was simpler. Patrick asked whether a person is truly getting 7-9 hours of sleep, getting 15-30 minutes of bright outdoor light within 30 minutes of waking, waking at about the same time daily, eating within 3 hours of bed, and drinking alcohol near bedtime. 5 The ideal answers were yes, yes, yes, no, and no. 5

Patrick's strongest study share was the hot-yoga depression thread on June 29. 10 The underlying trial randomized 80 adults with moderate to severe depression to 8 weeks of hot yoga in a 105°F room, 90 minutes per class and at least 2 classes per week, or to a waitlist control. 10 18 Patrick reported that IDS-CR depression scores fell by about 13 points, 59.3% of yoga participants had symptoms fall by at least 50%, and 44% reached near remission versus 6.3% in controls. 10 18 A 2026 dose-response analysis reported that each added yoga class was associated with an additional IDS-CR improvement of about 0.72 points, with beta = -0.72 and p < .005. 19

Patrick added the necessary caveat herself: hot yoga is "not a standalone replacement for mental health care." 10 That makes it an adjunct to discuss with a clinician, especially for people with heat intolerance, cardiovascular risk, pregnancy, medication interactions, or severe depression.

On July 1, Patrick reposted Brady Holmer's summary of a new Medicine & Science in Sports & Exercise paper on cardiorespiratory fitness and cytotoxic T-cell function. 11 The study measured VO2peak, body-fat percentage, and resting blood markers in 43 adults, including 16 women. 20 Higher cardiorespiratory fitness predicted cytotoxic T-cell fatty-acid and amino-acid oxidation capacity, beta = 0.362 and p = 0.017; glycolytic capacity, beta = 0.495 and p < 0.001; and IFN-gamma expression, beta = 0.384 and p = 0.011. 20 That is mechanistic support for fitness, not a shortcut around training.

The clearest divergence is metformin. Attia's July 4 article argues against metformin as a general anticancer or geroprotective drug and says positive signals should lead to narrower trials. 2 Sinclair, in contrast, said this week that he still takes extended-release metformin 1 g, alternating with berberine. 3 A reader should not average those positions into a middle-ground dose. The better move is to ask what indication is being treated, what endpoint is being measured, and what downside is acceptable.

The strongest convergence is immune and cancer biology, but it remains interpretive. Johnson's autoimmune gastritis thread, his cancer-Alzheimer's post, Patrick's T-cell fitness share, and Attia's metformin cancer review all touch immune function, cancer biology, or disease-specific risk. 1 13 20 2 The shared lesson is not that immune modulation is the new generic longevity lever. It is that disease context matters.

For personal action, the low-regret items this week are familiar: review persistent iron deficiency or unexplained symptoms with a clinician; pair GLP-1 weight loss with protein and resistance training; audit sleep timing; fuel long training sessions; and build cardiorespiratory fitness progressively. The high-uncertainty items are also clear: engineered cell therapies for autoimmune gastritis, oral chemical reprogramming, SL-100, and broad metformin use for cancer prevention need stronger public evidence before they belong in a personal longevity stack.