I’m taking a drug that could extend my life. I don’t care that it’s only been tested on mice

A weekly pill that stops ageing sounds like the stuff of science fiction. Yet evangelists for rapamycin claim it does exactly that

Rapamycin is a drug commonly prescribed to organ transplant patients to suppress their immune response. However, some experts suggest that it could do much more than that. Taken at a low dose, it could increase lifespan, dampen inflammation and prevent age-related diseases, such as dementia.
Research has shown promising results for its potential to extend life, first in a study on yeast, then in various animal studies, most notably a 2009 study on elderly mice that showed rapamycin extended lifespan by 14 per cent.
It is thought that rapamycin could lengthen the lifespan of humans in a similar way, by speeding up the body’s process of cellular recycling and thus keeping people healthier for longer. Dr Philip Borg, a longevity medicine specialist who does not prescribe rapamycin but has patients taking it, says that some patients report fewer grey hairs and aches and pains – as if the clock has literally been turned back.
Despite not yet being approved for use as an anti-aging drug, rapamycin is licensed in the UK for transplant patients and is available online from other countries with looser restrictions. It has become a social media sensation and is promoted by biohacking influencers such as Peter Attia and Bryan Johnson. Both have huge online followings. In his book Outlive: The Science and Art of Longevity, Attia says rapamycin “acts almost like a switch that inhibits a very specific cellular mechanism that exists in nearly everything that lives”.
Thousands of people are already taking rapamycin for longevity – they gather in forums and on social media to discuss its benefits and side effects. Many of them are in America, where it is easier to access the drug. However, there are people taking it worldwide.
“The simple answer is that we don’t know yet,” says Leslie Kenny, a longevity expert. What we know so far is that “rapamycin activates a cell renewal process called autophagy using a pathway called the mTOR pathway”, she says. “In Greek, autophagy just means self-eating, and it’s actually more like self-cleaning. It’s like the self-clean button on your oven – it allows our cells to reset. And research from the University of Oxford shows that, in elderly immune cells, autophagy actually rejuvenates those cells.”
The mTOR pathway is a cellular signalling pathway that regulates multiple processes in the body, including cell growth, metabolism and protein synthesis. By blocking these actions, a class of drugs called mTOR inhibitors – of which rapamycin is one – can be used to treat cancer and autoimmune diseases, as well as potentially slowing down the very process of ageing. Experts have compared the effects of rapamycin to that of fasting or “caloric restriction”, which is one of the proven ways to increase lifespan and health span (the amount of time a person lives free of disease).
Larry Hayes, 52, worked in artificial intelligence in Silicon Valley before moving back to the UK and starting a new career as a children’s author (by coincidence, one of his books is titled How to Survive the Future). He has been taking a small dose of rapamycin for the past two and a half years – 6mg weekly, on a pattern of eight weeks on, eight weeks off.
“People from California tend to be a bit over the top, but they were talking about feeling 10 years younger, and all of that stuff,” he says. “It’s worked in every organism they’ve tried it with, from yeast through nematodes [roundworms] through drosophila [fruit flies], all the way up to monkeys… My way of looking at it is, if it can turn a 52 year old me into a 42 year old me, that’s pretty good.”
He admits that he hasn’t seen the kind of transformative benefits described by the longevity acolytes in California. “But about 12 years ago I injured my shoulder by chopping wood, and it’s been an annoying niggle since then,” he says. “What I found is that within three weeks of starting rapamycin, it went and has been gone ever since. It’s obviously anecdotal, but it was a bit of a coincidence.”
He has also experienced what he believes is a boost in immune function, despite rapamycin’s function as an immunosuppressant at higher doses. Hayes’ wife works as a doctor and they have young children so they get colds “all the time”. Since he started taking rapamycin, he hasn’t been ill.
His experience chimes with the findings published in a 2014 study, which showed that in a group of adults aged 56 or over, those taking a different mTOR inhibitor called everolimus had a more significant antibody response to the flu vaccine than those who got a placebo.
Kenny urges caution for those considering jumping on the bandwagon, not least because it is still in the very early days of research in humans. “First of all, you have to make the jump from mice to humans,” says Kenny. “And that is a big jump. Research done on marmosets [monkeys] is interesting, a 10 per cent life extension, but in human trials, the reviews have either no benefit or mixed benefit.” There are also side effects to consider: the most common are mouth ulcers and rashes, but Kenny says people also experience slower wound healing.
Other experts agree. While the research is “certainly very promising, it’s not a drug without side effects”, says Borg. “The main ones I look for in my patients are an adverse lipid profile [cholesterol], and your glucose control can also become worse when you start taking it.” It is a relatively inexpensive, generic drug, he explains. “Some countries do not require a prescription to sell it to patients; there are online pharmacies and people order it from there and get it in the post.”
Not enough research has been done to establish whether there are long-term side effects. “The largest review of 2007 patients found no adverse events in patients who took it for an extended period of time,” he says. Another review asked 333 US-based individuals about rapamycin side effects and found that there were no serious adverse events. “That’s as much data as we have; it’s not great data, but from what we can see, it’s pretty well tolerated, but nothing is without risk.”
The experts unanimously agree that there are more important things you should be doing first to lengthen your health span. “Exercise number one, good social contact number two, sleep number three,” says Kenny. “It’s the stuff everyone already knows. People take it for granted and underestimate it because they think, no, surely that can’t be it, but we know from examining healthy centenarians around the world… They have an emphasis on movement, hiking up a hill to get their groceries, carrying a heavy load, working in the garden.”
An experimental drug should be, for the time being, last on the list. More important are “the basics of exercising regularly, making sure they’re metabolically healthy in terms of their glucose control, keeping muscle mass up”, says Borg. “Out of all the things that somebody could be doing, taking rapamycin would be the final one per cent – the final sprinkle.”
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