Silicon Valley longevity biohackers risk harm by self-trials

Silicon Valley – In 2019, venture capitalist Bryan Johnson began testing rapamycin on himself, cycling doses and schedules in search of longer life. By September 2024, he stopped—citing intermittent skin infections, high glucose levels, abnormalities in blood lipid levels, and

The first thing Bryan Johnson did wasn’t to ask a doctor. It was to start logging—daily, then weekly, then biweekly—his own body’s response to rapamycin, a drug better known for one purpose: preventing organ rejection after transplants.

In 2019, the 48-year-old technology entrepreneur and venture capitalist began taking rapamycin injections in an attempt to extend his life. He didn’t settle on one approach. He tested several protocols. including weekly and biweekly schedules. and he tried doses of 5 milligrams. along with 6-mg and 10-mg doses.

Then, in September 2024, he ended the trial.

Johnson said the benefits didn’t outweigh the drawbacks, laying out his reasoning in a post on social-media platform X. He reported intermittent skin infections, high glucose levels, abnormalities in his blood lipid levels, and a heightened resting heart rate. “With no other underlying causes identified. we suspected Rapamycin. and since dosage adjustments had no effect. we decided to discontinue it entirely. ” he wrote.

For people watching Silicon Valley’s longevity scene, Johnson’s experiment had become a kind of template. He isn’t just dabbling—he’s selling the tinkering as a science-forward pursuit of extra years. while publishing his life regimen widely through social media and other channels. Johnson often tinkers with drugs. peptides provided as supplements and injections. and other medical interventions as part of his Blueprint program. a self-published guide that has been adapted over time.

In work he and his team described to Nature, they said “the new focus of our protocol is to tackle chronic conditions that current medicine accepts as manageable but not treatable, and to render them treatable through advanced diagnostics and next-generation personalized therapeutics”.

But researchers who study ageing and longevity say the danger isn’t merely that these interventions remain unproven. It’s the way the results—often based on individuals rather than controlled trials—can spread faster than evidence.

Johnson’s Blueprint protocol has been adapted over time, and his role in popularizing “stacks” is now part of the story researchers tell about how longevity ideas migrate from wealthy influencers to the public.

There’s no medical intervention proven to extend human life by targeting ageing itself. Andrew Steele. an independent longevity researcher based in Berlin and author of the book Ageless (2022). told Nature. “There probably are things on our radars that might work, but nothing has ever been tried in humans.”.

In that gap—between what can be measured in a single person and what can be proven in thousands—researchers see a collision. Nir Barzilai. president of the Academy of Geroscience and a genetics researcher at Albert Einstein College of Medicine in New York City. said he’s torn. In his view, interventions like Johnson’s tinkering are often rooted in biology, not nonsense. But they’re not rooted in clinical evidence. “If you’re asking. ‘Is he taking something that doesn’t make sense?’ I would say. no. these things are based on biology but not on clinical evidence. ” Barzilai said.

Steele and Barzilai aren’t dismissing the whole movement. Both say that some protocols being tested and touted by Silicon Valley elites could have meaningful impact on lifespan and healthspan—the time during which people are not affected by chronic disease and disabilities related to ageing. The problem is that the evidence isn’t there yet.

Matt Kaeberlein. a biogerontologist who founded the Healthy Aging and Longevity Research Institute at the University of Washington in Seattle. calls the current situation “a signal-to-noise problem.” In the limited data available. he said. “there’s signal there. but there’s a whole lot of noise”. That makes it hard for the public to separate the two.

Faye Mythen. an entrepreneur and founder of Reborne Longevity. a preventative-medicine and longevity clinic in London. uses a phrase that lands like a warning: “shadow phase two.” It refers to a stage of drug trials that is tightly regulated—an intermediate step between early research and large-scale confirmation. In her telling, high-profile tech founders and famous people with money can run experiments on themselves anyway. “You have all of these tech founders and famous people with lots of funds running shadow experimentations on themselves. and then it goes straight to the population. ” Mythen said.

She added that these protocols can become accepted reference points, even though they aren’t. “You need to run clinical trials on thousands and thousands of people, with very carefully controlled reference points, to have acceptable data.”

At her clinic, Mythen said clients increasingly arrive with references to Johnson and his Blueprint protocol before any biomarker measurement has been done. “People ask for ‘the Blueprint,’ or for a specific molecule by name, before they have had a single biomarker measured,” she said.

Other researchers described similar experiences. Steele said his wife, a physician with an interest in longevity, gave a talk in Munich, Germany, and the first question she got was about Bryan Johnson.

It isn’t only rapamycin that shows how the longevity conversation moves. For years. supplements known as exogenous ketones—marketed to raise ketone levels in the blood. lower blood glucose and supposedly improve cognition—were widely embraced in Silicon Valley circles and sold as premium cognition aids and stimulants for executives.

Then. in March. entrepreneur Tim Ferriss and venture capitalist Kevin Rose used their popular podcast to warn listeners about supplements containing a compound called 1. 3-butanediol. Ferriss said emerging data from animal models indicate the compound might give mice a condition similar to fatty liver disease. “Treat it like ethanol. ” he warned. “like you’re drinking moonshine and you wouldn’t want to do that every day.” The animal findings have not been confirmed in human studies. and some manufacturers dispute the characterization.

That supplement became part of a longer list of life-extension tricks adopted by tech leaders despite uncertainty about effectiveness and safety. In 2019 and again in 2024. the US Food and Drug Administration warned against “young plasma” infusions—blood transfusions from young individuals that are promoted as an anti-ageing therapy. Johnson regularly incorporates these infusions into his wellness regimen, courtesy of his son.

Peter Thiel. the tech entrepreneur and billionaire. told Bloomberg News in 2014 that he takes human growth hormone in hopes of living for 120 years. The Mayo Clinic warned of substantial risks. and said there is little evidence that the drug helps healthy adults regain youth or energy. Thiel did not respond to Nature’s questions about whether he still takes the hormone or what he makes of the Mayo Clinic’s guidance.

In hopes of enhancing cognition. some tech leaders touted methylene blue. a compound with a long history as a textile dye that has been approved for limited medical use. mainly to treat a rare blood disorder. Others promoted nicotine pouches marketed as an alternative to smoking, despite concerns about addiction.

Margje Camps. a researcher at the University of Utrecht in the Netherlands who studies health influencers. said these figures often translate early-stage science for the public. turning preliminary or anecdotal findings into “stacks” that combine supplements. other compounds. protocols and therapies long before FDA approval. “It’s a trickle-down effect due to the nature of platforms they use to spread their content,” Camps said.

But the same researcher-focused concern repeats: biohacks promoted by social media influencers have not been clinically tested, leaving open the question of whether they work or might harm people.

The rapamycin story offers a concrete example of how far the scientific timeline is from the influencer timeline.

In animals, rapamycin has shown lifespan effects. Research has shown the immunosuppressant could extend the lifespan of mice by between 23% and 60% by inhibiting the mTOR pathway. a cascade of chemical reactions that regulates cell growth and is implicated in ageing. Kaeberlein said the evidence “works in every animal where it’s ever been tested.”.

But humans are different, and drug risks scale differently. The longer timelines required to show lifespan extension in people collide with the realities of side effects and clinical uncertainty. Barzilai pointed to a 2014 study involving everolimus. a rapamycin analogue. showing improved responses to vaccination against influenza in more than 200 adults aged 65 years and older. A follow-up phase II trial in 2018 found the drug reduced respiratory-tract infections in older individuals over one year.

In 2023, Kaeberlein and his team reported survey results of 333 people who had taken rapamycin off-label, mostly for anti-ageing purposes. The researchers found that “rapamycin users generally reported perceived improvements in quality of life.” But the team said the study is limited because it relied on self-reports. They also said they can’t rule out that people who experienced negative effects and stopped taking the drug were underrepresented.

There’s also the broader problem of what people assume is enough evidence. Camps said it has become normal for people to assume they need a supplement: “That’s become a regular thing. ‘Everyone is using them. surely I need one.’” Some influencers even sell supplements under their own brand names. creating financial incentives that may not always be obvious to followers.

Researchers argue that this environment makes it too easy for “n-of-1” results—what Steele called personal observations—to become de facto proof.

Steele and Barzilai both said researchers are watching the field carefully, not scoffing at it. Yet the gap between personal measurement and clinical confirmation remains the central tension.

Barzilai summarized the core issue with a line that doesn’t leave room for ambiguity: “Science is not on n = 1.”

Johnson and his Blueprint science team offered their own framing. They told Nature that randomized control trials remain the gold standard for evaluating single therapies or interventions. but they consider n-of-1 measurement “the next frontier.” They said these single-person assessments enable more-detailed measurements than are practical in a clinical trial. “We have already generated signals that lie beyond the published literature and constitute first-in-human observations,” they said.

Kaeberlein and Steele also discussed cost and feasibility. Steele estimated that a properly powered rapamycin trial in healthy adults would cost in the region of $50 million–$100 million. describing it as a minor fraction of the net worth of some of the extremely wealthy people in the longevity scene on social media. Steele called it “simultaneously a wellness fad and potentially the greatest revolution in the history of medicine. ” adding that he “haven’t yet worked out a way to take that multibillion-dollar excitement and redirect it into actual science.”.

David Gems. a researcher in biogerontology at University College London’s Institute of Healthy Ageing who has been working in the field since the early 1990s. said the appeal is psychological as much as scientific. “It gives people a feeling of control,” he said. “It’s hubris from tech-bro people. They think that because they’ve had so much success, they could beat ageing.”.

Johnson’s decision to discontinue rapamycin after reporting a cluster of side effects—intermittent skin infections, high glucose levels, abnormalities in his blood lipid levels, and a heightened resting heart rate—should have been a stop sign rather than a datapoint.

Instead. the broader question for the longevity world is how many people will act on these signals before clinical evidence catches up. When people build “stacks” around a single person’s experience, the risk isn’t just that the intervention may fail. It’s that it may be harmful—precisely the harm that Johnson himself reported when he finally pulled the plug on a trial he began in 2019.

This article was reproduced with permission and was first published on June 16, 2026.

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