Silicon Valley’s longevity biohackers are engaged in a dangerous experiment

In 2019, entrepreneur Bryan Johnson began a self-experimentation regimen involving daily injections of rapamycin. This drug, commonly used to prevent organ rejection post-transplant, served a different purpose for the 48-year-old technology entrepreneur and venture capitalist: to prolong his life.

Johnson explored multiple protocols, varying the frequency and dosage of rapamycin injections to assess their effects. He experimented with 5-milligram doses as well as 6-mg and 10-mg doses, on different schedules such as weekly and biweekly. However, by September 2024, he concluded that the potential advantages of rapamycin did not justify the side effects. As he noted in a social media post on platform X, he experienced recurring skin infections, elevated glucose levels, irregularities in blood lipid levels, and an increased 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.

Having sold his mobile-payment company Braintree to PayPal in 2013 for US$800 million, Johnson regularly modifies his daily regimen of drugs, peptides, both as supplements and injections, and other medical interventions, all in pursuit of extending his lifespan. He is among a growing number of tech entrepreneurs pursuing longevity through self-experimentation, sharing their findings on social media and other platforms.

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Johnson’s Blueprint protocol — his self-published guide on lifestyle and medical decisions — has evolved over time. He and his team informed Nature that “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”.

Similar to Johnson’s experience with rapamycin, many biohacking influencers often cease using products they once believed would extend their lifespans. For years, exogenous ketones—supplements that increase ketone levels in the blood, lower glucose levels, and are claimed to enhance cognition—were highly popular in Silicon Valley, marketed as premium cognitive enhancers and stimulants for executives.

In March, entrepreneurs Tim Ferriss and Kevin Rose cautioned their podcast listeners about supplements containing 1,3-butanediol. Ferriss mentioned that animal studies suggest it might cause a liver condition similar to fatty liver disease in mice, advising, “Treat it like ethanol,” and warning against daily consumption. These findings have not been confirmed in humans, and some manufacturers contest this characterization.

This supplement is among several life-extension methods favored by tech leaders, despite uncertainties surrounding their effectiveness and safety. In both 2019 and 2024, the US Food and Drug Administration (FDA) issued warnings against ‘young plasma’ infusions, where recipients receive blood transfusions from young donors. Marketed as anti-ageing therapies, these infusions are a regular part of Johnson’s wellness routine, with the help of his son.

Tech entrepreneur and billionaire Peter Thiel shared with Bloomberg News in 2014 his use of human growth hormone to potentially live to 120 years. This is despite the Mayo Clinic’s warnings about significant risks and limited evidence of the drug’s benefits for healthy adults. Thiel declined to comment to Nature about his continued use of the hormone or his thoughts on the Mayo Clinic’s guidance.

In pursuit of cognitive enhancement, some Silicon Valley tech leaders have promoted methylene blue, a compound historically used as a textile dye and approved for limited medical treatment of a rare blood disorder. They also advocate for nicotine pouches—marketed as a smoking alternative—as a method to boost focus and energy, despite well-known addiction risks.

These affluent longevity advocates are often considered interpreters of early scientific research to the general public, transforming preliminary or anecdotal results into so-called stacks that combine supplements, compounds, protocols, and therapies, long before receiving FDA approval. “It’s a trickle-down effect due to the nature of platforms they use to spread their content,” explains Margje Camps, a researcher at the University of Utrecht in the Netherlands who studies health influencers.

However, this trend is not without risk: experts in ageing and longevity caution that these biohacks lack clinical testing, making their efficacy and safety uncertain.

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

Biological basis

Nir Barzilai, president of the Academy of Geroscience and a genetics researcher at Albert Einstein College of Medicine in New York City, has mixed feelings about the impact of biohackers. Johnson’s experimentation with various supplements and drugs is often based on some 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,” says Barzilai.

Neither Steele nor Barzilai are entirely skeptical. Both acknowledge that some protocols being tested and promoted by Silicon Valley elites could meaningfully affect lifespan and healthspan—the period during which people are free from chronic diseases and age-related disabilities. Yet, concrete evidence is still lacking.

This gap is the primary concern for researchers. Matt Kaeberlein, a biogerontologist who founded the Healthy Aging and Longevity Research Institute at the University of Washington in Seattle, describes it as a “signal-to-noise problem”.

In the limited data available on these interventions, he states, “there’s signal there, but there’s a whole lot of noise”. This makes it challenging for the public to distinguish between the two.

Faye Mythen, an entrepreneur and founder of Reborne Longevity, a preventative-medicine and longevity clinic in London, refers to influencers with substantial social-media followings as a “shadow phase two” problem, referencing the regulated middle stage of pharmaceutical drug trials. “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,” she says. “Those protocols become a sort of accepted reference point, which they are not. You need to run clinical trials on thousands and thousands of people, with very carefully controlled reference points, to have acceptable data.”

Mythen’s company typically examines clients’ biomarkers, cellular biology, and genetics to predict future risks and then offers tailored treatments to help prevent potential issues. However, she notes that clients now frequently come to the clinic referencing Johnson and his Blueprint protocol.

“People ask for ‘the Blueprint,’ or for a specific molecule by name, before they have had a single biomarker measured,” Mythen observes.

Other researchers quoted by Nature report similar experiences: Steele mentions that his wife, a physician interested in longevity, gave a presentation in Munich, Germany. “The first question she got was about Bryan Johnson.”

Evidence from trials

Influencers promoting wellness products is not new. For example, billionaire entrepreneur Kim Kardashian has advertised detox teas and red-light therapy over the years. However, the recent wave of ‘tech bro’ (all those Nature analyzed were men) life hackers are distinct because they incorporate scientific details into their decisions and how they share them. By referencing technical concepts like lipid panels, mTOR inhibitor dose volumes, and biological ages, they use scientific terminology to market interventions despite the lack of definitive research—a distinction that might elude most people.

“It’s become normal for people to assume that they need a supplement,” Camps states. “That’s become a regular thing. ‘Everyone is using them, surely I need one.’” Some influencers in the longevity arena even sell supplements under their brand names on their websites and through their social-media platforms, meaning they have a financial interest in the products they promote, a connection that may not always be obvious to followers.

Regarding the scientific research on longevity products, very little has been conducted on humans. Take rapamycin, which Johnson has stopped using but remains a topic of discussion online. Studies have shown that the immunosuppressant could extend the lifespan of mice by 23% to 60% by inhibiting the mTOR pathway, a series of chemical reactions that regulate cell growth and is linked to ageing. Those studies and others indicate potential lifespan-enhancing results. “It works in every animal where it’s ever been tested,” Kaeberlein comments. However, demonstrating lifespan extension in humans is more challenging due to the timescales involved and the risks associated with drugs like rapamycin.

When questioned about evidence of mTOR inhibitors providing health benefits or life-extending properties in humans, researchers who spoke to Nature frequently cited a study published over a decade ago, in 2014. It tested a rapamycin analogue called everolimus and found that the drug improved responses to influenza vaccination in more than 200 adults aged 65 and older. A subsequent phase II trial in 2018 showed that the drug reduced respiratory-tract infections in older individuals over one year. In 2023, Kaeberlein and his team reported survey results from 333 people who had taken rapamycin off-label, primarily for anti-ageing reasons. The researchers found that “rapamycin users generally reported perceived improvements in quality of life”. However, they acknowledge that the study is limited because it relied on self-reports, and they could not rule out the possibility that the survey lacked representation from individuals who experienced negative effects and stopped taking the drug.

Another source of evidence for longevity effects in humans comes from drugs that have already received regulatory approval for use in chronic conditions linked to ageing, according to Barzilai. He highlights four FDA-approved drugs or drug classes with reasonable evidence of slowing age-related diseases. He is most enthusiastic about metformin—a cost-effective, decades-old diabetes drug that he and colleagues are currently testing for its ability to delay the development or progression of age-related chronic diseases in a trial called TAME. Another is the class of weight-loss drugs known as GLP-1 receptor agonists—such as Ozempic—that appear to affect ageing hallmarks independently of weight loss. The last two drug classes are SGLT2 inhibitors, which prompt the body to excrete more glucose through urine than usual and appear to have cardiovascular and kidney benefits, and bisphosphonates, which enhance bone health.

Despite this promise, Barzilai, like other gerontologists, worries that anecdotal accounts from a few wealthy tech titans could do more harm than good. “Science is not on n = 1,” Barzilai remarks.

Johnson and his Blueprint science team informed Nature that while randomized control trials remain the gold standard for evaluating single therapies or interventions, “we regard n-of-1 measurement as the next frontier”. These individual assessments allow for more detailed measurements than are feasible in a clinical trial. “We have already generated signals that lie beyond the published literature and constitute first-in-human observations,” they state.

Funding large trials to test anti-ageing interventions in humans might be within reach for some influencers, but whether they would choose to allocate their resources this way remains uncertain. Steele estimates that a properly powered rapamycin trial in healthy adults would cost between $50 million and $100 million—a small fraction of the net worth of some of the ultra-wealthy individuals leading the longevity scene on social media. “It’s simultaneously a wellness fad and potentially the greatest revolution in the history of medicine,” he asserts. “And I haven’t yet worked out a way to take that multibillion-dollar excitement and redirect it into actual science.”

Regarding the social-media buzz about the latest shortcuts, “it gives people a feeling of control,” says David Gems, a biogerontology researcher at University College London’s Institute of Healthy Ageing, who has worked in the field since the early 1990s. “It’s hubris from tech-bro people. They think that because they’ve had so much success, they could beat ageing.”

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