Rapamycin, growth hormone, ketones, plasma exchange, methylene blue, and nicotine patches have become part of Silicon Valley's longevity culture. Some of the methods draw cues from animal experiments, but there is still no medical treatment that has been proven to extend human life by slowing the aging process.
In 2019, tech entrepreneur Brian Johnson began using rapamycin, an immunosuppressant drug used, among other things, to prevent organ transplant rejection. His goal was not to treat a disease he had been diagnosed with, but rather to try to slow down aging and extend his life.
Johnson has tried various treatment regimens over the years, monitoring a wide range of physical parameters. In September 2024, he decided to stop using rapamycin. He said he suffered from recurrent skin infections, elevated glucose levels, changes in blood lipids, and an increased resting heart rate. After no other explanation for the symptoms was found and no improvement occurred following the change in regimen, his program team suspected the drug.
The case illustrates the central contradiction in the “biohacking” culture that has developed among tech entrepreneurs, investors and influencers: Many of the substances they are testing have a possible biological explanation and sometimes even impressive results in mice, worms or dogs. But the road from here to proving that they extend the life of a healthy person is still a long one.
The man who turned his body into a laboratory
Johnson sold payments company Braintree to PayPal in 2013 for about $800 million. In recent years, he has become one of the most recognizable faces in the longevity movement, using the Blueprint program—a changing system of diet, exercise, medical tests, medications, supplements and experimental treatments.
According to his people, the focus of the program has gradually shifted from a general attempt to “rejuvenate” the body to an attempt to diagnose and treat chronic diseases with personalized means, advanced tests, and new treatments.
But the frequent changes in the protocol also highlight its limitations. When a single person is taking multiple medications and supplements, changing their diet, exercising, sleeping on a regular schedule, and undergoing various medical treatments, it is difficult to know which component caused a particular change – or whether the change would have occurred without it.
Such a self-experiment does not include a control group, random assignment, or blinding. It may also retrospectively select only those measures that appeared positive, while other measures did not change or even worsened.
Why is rapamycin so exciting?
Rapamycin inhibits a cellular pathway known as mTOR, which regulates growth, cell division, metabolism, and response to nutrient availability. The activity of this pathway has been linked to aging and several age-related diseases.
In experiments on mice, rapamycin extended lifespan significantly. In some circumstances, an extension of tens of percent has been reported, and in one experiment, temporary treatment of older mice extended their remaining lifespan by up to 60%.
Such findings make mTOR inhibition one of the most promising directions in aging research. But a mouse is not a human, and extending the life of a laboratory animal does not prove that the same drug will extend the lives of healthy people.
In small clinical trials in adults, rapamycin and similar drugs have been tested primarily on measures of immune function. In a randomized study of 264 adults, controlled inhibition of TORC1 was associated with improved response to influenza vaccination and a reduction in the number of infections reported during follow-up.
These are interesting results, but the experiment did not test whether the participants lived longer. Studies in dogs have also so far mainly examined safety, tolerability, and physiological indicators – there is no definitive proof of life extension.
The use of rapamycin also carries risks. When given in medical doses, it can suppress the immune system, affect blood sugar and lipid levels, delay wound healing, and increase the risk of infections. There is currently no medical consensus on its use in healthy people to prolong life.
The ketones that went from a luxury supplement to a warning
“Exogenous ketone” supplements have become popular among executives and tech entrepreneurs in recent years. They aim to raise blood ketone levels without the user having to fast or follow a ketogenic diet.
They were marketed as a way to improve concentration, reduce glucose, and provide energy to the brain. One of the ingredients used in some of the products is 1,3-butanediol, which the body can convert into ketone bodies.
In March 2026, entrepreneur and podcaster Tim Ferriss and venture capitalist Kevin Rose warned against routine use of products containing the substance, citing emerging data from animal studies that raised concerns about liver damage similar to fatty liver disease.
These data have not yet been validated in human clinical studies, and industry manufacturers dispute the interpretation. The affair illustrates how a supplement can quickly become a hit with influencers – and then cause concern, even before adequate human studies have been conducted.
“Young Blood”: An Intriguing Idea in Mice, an Unproven Treatment in Humans
Studies that combined the blood systems of young and old mice have sparked interest in the possibility that components in young blood could affect aging tissues. In the wake of these studies, companies have begun offering plasma transfusions from young donors as a treatment for aging, memory loss, and degenerative diseases.
The U.S. Food and Drug Administration warned against such treatments in 2019 and reiterated the warning in December 2024. According to the administration, there is no controlled evidence that plasma infusions from young donors prevent aging, improve memory, or treat diseases such as Alzheimer's and Parkinson's.
Plasma transfusions are not without risk. They can cause allergic reactions, respiratory complications, and the transmission of disease agents. Plasma is used in medicine for specific conditions, such as blood clotting disorders, but has not been approved as a treatment for normal aging.
Johnson participated in an intergenerational plasma exchange trial with his son and father in 2023. After six treatments, including one with plasma from his son, he reported no benefit in his blood, imaging, and equipment tests—and stopped the trial. He later underwent other plasma exchange procedures, which are not the same as receiving plasma from a younger person.
Peter Thiel and growth hormone
Technology entrepreneur and investor Peter Thiel said in a 2014 interview that he uses human growth hormone in the hope of living to the age of 120. It is unknown whether he continues to do so today.
Growth hormone is produced naturally in the pituitary gland, and its levels gradually decline after puberty. Synthetic hormone is used to treat diagnosed medical deficiencies and some other specified conditions.
In healthy adults, it may increase muscle mass and reduce fat, but the increase in muscle mass does not necessarily translate into an increase in strength. There is no convincing evidence that it restores youth or extends life.
Its use in healthy people may cause edema, joint and muscle pain, carpal tunnel syndrome, high blood sugar, and type 2 diabetes. There is also concern about an increased risk of some types of cancer.
Methylene blue and nicotine sachets
Another substance that has gained attention in biohacking circles is methylene blue. This is a compound that was once used as a textile dye, but it also has specific medical uses – primarily in the treatment of methemoglobinemia, a rare blood disorder in which hemoglobin’s ability to transport oxygen is impaired.
Some influencers tout it as a substance that improves mitochondrial activity, brain energy, and cognitive function. However, approved medical use for a specific condition does not prove efficacy in healthy people, certainly not life extension.
At the same time, nicotine sachets are being marketed among some techies as a means of increasing concentration, alertness, and energy. Nicotine does affect the nervous system, but it is also an addictive substance. A temporary improvement in alertness is not a treatment for aging and is not evidence of extending life expectancy.
How does a hypothesis become a “stack” of treatments?
Longevity influencers often act as intermediaries between primary research and the public. A small study in mice, a short human experiment, or an interesting cellular mechanism becomes a recommendation on social media for a “stack” – a combination of drugs, supplements, hormones, and treatment methods.
Marja Kempes of Utrecht University, who studies health influencers, describes this as a trickle-down effect. Wealthy people with large audiences present personal experiments, and the content is gradually copied by users who do not enjoy the same level of medical surveillance.
Entrepreneurs' business success can also foster overconfidence in their ability to solve biological problems. Success in starting a software company does not guarantee that a person knows how to design a clinical trial or distinguish between statistical correlation and causation.
Self-experimentation can be speculative, but it is no substitute for controlled research. Even when measures improve, it is not always clear whether they predict longer life. A “biological age” measured by a commercial test, for example, is not necessarily a validated medical target.
“Phase Two Experiment in the Shadows”
Experts have described what is happening as a kind of “phase two shadow trial”: rich and famous people are testing unproven treatments on themselves, without a uniform protocol and without a control group, and then publishing the results as if they were medical knowledge.
The problem isn't just that the methods may not work. They can cause direct harm, create interactions between drugs and supplements, encourage people to spend large amounts of money, or divert them from proven treatments.
Andrew Steele, independent longevity researcher and author of the book Ageless, emphasizes that there is still no medical intervention that has been proven to extend human life by directly affecting the aging process. He says there are several options that may prove effective – but they have not yet been properly tested in humans.
The money is there – the big experiment is not yet
One of the difficulties in the field is that a real life extension trial requires a long time, thousands of participants, and monitoring of significant medical outcomes. It is difficult to wait decades to see if people live longer.
Researchers can use intermediate measures, such as disease onset, physical function, frailty, or immune response, but there is still no single measure that is recognized as a reliable proxy for life expectancy.
According to the estimate quoted in the article NatureA large, controlled trial of rapamycin in healthy people could cost between $50 million and $100 million. That’s a large sum for academic research, but small compared to the fortunes of some longevity promoters and the tens of billions of dollars generated by the nutritional supplement market.
This gap is drawing criticism: Instead of funding controlled experiments that could answer the questions, some of the wealthy are investing millions in personal monitoring and treatments that do not allow general conclusions to be drawn.
Between a health fad and a possible medical revolution
Public interest in longevity is not necessarily without merit. Aging is a major risk factor for many diseases, including cancer, heart disease, neurodegenerative diseases, and frailty. Delaying some of the biological processes associated with age may in the future delay several diseases at the same time.
The study of aging is a serious scientific field, and rapamycin, mTOR inhibition, senolytic drugs, and epigenetic reprogramming are real research directions. The problem begins when the scientific possibility is presented to the public as an already proven treatment.
The biohacking culture is therefore a combination of two different things: a health fad that is sometimes based on marketing and exaggeration, and alongside it the possibility of a real medical revolution – if the methods are tested in randomized, controlled, and long-term trials.
Today, the methods proven to reduce morbidity and mortality are no billionaire secrets: avoiding smoking, exercising, eating a balanced diet, getting enough sleep, getting vaccinated, and treating risk factors like blood pressure and cholesterol. They may be less exciting than plasma exchange or stacking supplements, but the evidence behind them is much stronger.
FAQ
Has rapamycin been proven to extend human life?
No. It has extended life in several animal species, and small human trials have suggested possible effects on the immune system. It has not been shown to extend the lives of healthy people.
Can a plasma transfusion from a young person rejuvenate an older person?
There is no controlled clinical evidence for this. The FDA warns that “young plasma” has not been approved as an aging treatment and that plasma transfusions also have medical risks.
Why are billionaires' self-experiments not considered scientific evidence?
Because they do not have a control group, random assignment, or the ability to separate the effects of multiple treatments, a result in one person does not prove that the treatment caused it or that it will work in others.
Is there currently a proven medical treatment against aging itself?
No. It is possible to reduce the risk of disease and extend life expectancy through preventive medicine and proven habits, but there is currently no treatment that has been proven to slow biological aging and directly extend human life.
Notes:
The strongest human evidence cited for mTOR inhibition concerns limited improvements in immune parameters and reduced infections in a study of 264 adults—not an increase in lifespan. (PubMed(The FDA states that there are no controlled studies showing clinical benefit from “young plasma,” and lists risks of infections, allergic reactions, and respiratory complications.)US Food and Drug Administration(The Mayo Clinic also emphasizes that there is insufficient evidence for the use of growth hormone against aging and lists metabolic and other risks.)Mayo Clinic)
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One response
Forget it, death is part of life. Even if they extend it, at what cost will they be able to stop the aging of all organs, especially the brain? Whoever wants to stay alive with dementia needs a human replacement. Humans are just stuck with a fantasy.