In 2019, entrepreneur Bryan Johnson began to experiment on himself by taking daily injections of rapamycin. This immunosuppressant drug is typically used to prevent organ rejection after transplants, but the 48-year-old technology entrepreneur and venture capitalist had a different goal — to extend his life.

He tested several protocols, experimenting with weekly, biweekly and other schedules. He tried 5-milligram doses as well as 6-mg and 10-mg ones. But in September 2024, Johnson decided to end his personal trial with rapamycin: the benefits didn’t outweigh the drawbacks, which Johnson outlined in a post on social-media platform X. He had intermittent skin infections, high glucose levels and abnormalities in his blood lipid levels, plus 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.

Johnson, who sold his mobile-payment business Braintree to financial-technology firm PayPal in 2013 for US$800 million, often tinkers with his daily regimen of drugs, peptides in the form of both supplements and injections and other medical interventions in pursuit of a longer life. He’s part of a growing crowd of tech entrepreneurs who are seeking extra years by hacking their own bodies — and sharing their exploits widely through social media and other channels.

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Johnson’s Blueprint protocol — a self-published guide to his life changes and medical choices — has been adapted over time. He and his team told 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”.

As with Johnson and rapamycin, it’s not uncommon for these biohacking influencers to suddenly stop using a product that they previously thought would help them to extend their lives. For years, supplements called exogenous ketones — which raise ketone levels in the blood, lower blood glucose and supposedly improve cognition — were widely embraced in Silicon Valley circles. The compounds were sold as a premium cognition aid and a stimulant for executives.

In March, however, entrepreneur Tim Ferriss and venture capitalist Kevin Rose used their popular podcast to warn listeners about taking supplements that contain a compound called 1,3-butanediol. Emerging data from animal models, said Ferriss, indicate that it 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.

This supplement joins a long list of life-extension tricks that tech leaders have latched onto despite questions about their effectiveness and safety. In 2019 and again in 2024, the US Food and Drug Administration (FDA) warned against ‘young plasma’ infusions, in which people receive blood transfusions from young individuals. These infusions are being promoted as an anti-ageing therapy — and are something that Johnson regularly incorporates into his wellness regimen, courtesy of his son.

Tech entrepreneur and billionaire Peter Thiel told Bloomberg News in 2014 that he takes human growth hormone in hopes of living for 120 years, despite the Mayo Clinic, a renowned US medical centre, warning of substantial risks and saying that there is little evidence that the drug helps healthy adults to 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 Silicon Valley tech leaders have 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. And they are promoting nicotine pouches — marketed as an alternative to smoking — as a way to optimize focus and energy, despite well-documented concerns about addiction.

These wealthy longevity evangelists are often seen as translators of early-stage science to the public, who turn preliminary or anecdotal findings into so-called 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,” says Margje Camps, a researcher at the University of Utrecht in the Netherlands who studies health influencers.

But there is a danger to this growing phenomenon: researchers who study ageing and longevity warn that these biohacks have not been clinically tested, meaning that it’s unclear whether they work or might harm people.

There is no medical intervention that is proven to extend human life by targeting ageing itself, says Andrew Steele, an independent longevity researcher based in Berlin and author of the book 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, is torn about the impacts that the biohackers have. Take Johnson’s tinkering with various supplements and drugs, which is usually based on some kind of 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 cynics. Both say that some of the protocols being tested and touted by Silicon Valley elites could have a meaningful impact on lifespan and healthspan — the time during which people are not affected by chronic disease and disabilities related to ageing. But the evidence isn’t there yet.

That gap is what concerns researchers most. Matt Kaeberlein, a biogerontologist who founded the Healthy Aging and Longevity Research Institute at the University of Washington in Seattle, calls it “a signal-to-noise problem”.

In the limited available data about these interventions, he says, “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, calls tinkerers with outsized social-media followings a “shadow phase two” problem, referring to 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 analyses clients’ biomarkers, cellular biology and genetics to predict future risks and then offers tailored treatments to help people to prevent potential issues. But she says that her clients now routinely arrive at the clinic citing 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,” says Mythen.

Other researchers that Nature spoke to report similar experiences: Steele says that his wife, a physician with an interest in longevity, gave a talk in Munich, Germany. “The first question she got was about Bryan Johnson.”

Evidence from trials

It is not new for influencers to tout wellness products: billionaire entrepreneur Kim Kardashian, for example, has promoted a range of detox teas and red-light therapy over the years. But the most recent crop of ‘tech bro’ (all those Nature analysed were men) life hackers offer something different because they embrace scientific details — both in their decisions and in how they publicize their choices. By referencing nerdy concepts such as lipid panels, mTOR inhibitor dose volumes and biological ages, they use scientific terminology to promote interventions even though definitive research is lacking — a distinction most people might not make.

“It’s become normal for people to assume that they need a supplement,” says Camps. “That’s become a regular thing. ‘Everyone is using them, surely I need one.’” Some influencers in the longevity space also sell supplements under their own brand names on their websites and through their social-media platforms, meaning that they have commercial interests in the products they discuss, a relationship that might not always be apparent to followers.

Of the science that does exist regarding longevity products, very little work was done in humans. Take rapamycin, which Johnson has stopped using, but others online are still discussing. Research has shown that 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. That study and others show potentially lifespan-enhancing results. “It works in every animal where it’s ever been tested,” according to Kaeberlein. However, it is more difficult to show lifespan extension in humans because of the timescales involved and risks associated with drugs such as rapamycin.

When asked whether there was any evidence for mTOR inhibitors having health benefits or life-extending properties in people, researchers who spoke to Nature often cited a study published more than a decade ago, in 2014. It tested a rapamycin analogue called everolimus and found that the drug 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 that the drug reduced respiratory-tract infections in older individuals over one year. In 2023, Kaeberlein and his team reported on 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 says that the study is limited because it relied on self-reports and the scientists can’t rule out the possibility that the survey lacked representation from people who experienced negative effects and stopped taking the drug.

Another source of evidence for longevity effects in people comes from drugs that have already been given regulatory approval for use in chronic conditions that have links to ageing, says Barzilai. He points to four FDA-approved drugs or drug classes that he says have reasonable evidence of slowing age-related diseases. He’s most excited about metformin — a cheap, 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 seem to affect ageing hallmarks independently of weight loss. The last two drug classes are SGLT2 inhibitors, which compel the body to excrete more glucose through urine than usual, and that seem to have cardiovascular and kidney benefits; and bisphosphonates, which improve bone health.

Despite this promise, Barzilai, like other gerontologists, fears that anecdotal accounts by a few rich and famous tech titans could do more harm than good. “Science is not on n = 1,” says Barzilai.

Johnson and his Blueprint science team told Nature that although randomized control trials remain the gold standard for evaluating single therapies or interventions, “we regard n-of-1 measurement as the next frontier”. 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 say.

Funding for large trials to test anti-ageing interventions in humans could be within some influencers’ reach, but whether they would choose to spend their money in that way is a separate question. A properly powered rapamycin trial in healthy adults would cost in the region of $50 million–$100 million, estimates Steele — a minor fraction of the net worth of some of the extremely wealthy people at the vanguard of the longevity scene on social media. “It’s simultaneously a wellness fad and potentially the greatest revolution in the history of medicine,” he says. “And I haven’t yet worked out a way to take that multibillion-dollar excitement and redirect it into actual science.”

As for the social-media whispers of the latest shortcuts, “it gives people a feeling of control”, says David Gems, researcher in biogerontology at University College London’s Institute of Healthy Ageing who has been working 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.