Of the 54 molecules tested for lifespan effects by the National Institute on Aging’s Interventions Testing Program, rapamycin is the one researchers trust most. A review of the program’s first two decades, published in the Journal of Gerontology, put the gain at roughly 15 to 20 percent more life in mice, and it held across sex, age at the start of treatment and dosing strategy.
The program, launched in 2004, is regarded as the gold standard in aging research because every compound is tested at three independent sites in diverse mouse models. Pairing drugs looks better still. Rapamycin plus acarbose raised median lifespan by up to 36.6 percent, the review found. Another candidate, the diabetes drug class known as SGLT2 inhibitors, added 13.6 percent in male mice.
What happened in people
Mice are one thing. The more interesting evidence from 2025 came from human trials, and most of it is small.
The PEARL trial ran 48 weeks, double-blind and placebo-controlled, in healthy adults roughly 50 to 85 years old. Participants took placebo, 5 mg or 10 mg of compounded rapamycin once a week. The main target, visceral fat, did not differ between groups. But women on the 10 mg dose gained lean mass, a 6 percent change from baseline, and reported less pain. Emotional well-being and general health also improved, and serious adverse events were no more common than on placebo.
A second pilot, published in GeroScience, was tiny: six healthy men aged 70 to 76 took 1 mg of rapamycin daily for eight weeks. Cardiac MRI showed better diastolic function, and blood-vessel function improved too. The authors reported no adverse events directly related to the drug.
Neither study measured lifespan, and the cardiovascular trial had six participants. Researchers writing about the work call it proof of concept that justifies larger, controlled trials.
Old reputation, new doses
For years rapamycin was tied almost entirely to transplant patients, where it suppresses the immune system. That left many clinicians wary of using it preventively. The recent trials used low doses, either weekly or at 1 mg a day, and that is the part of the story that changed.
The reviewers behind the PEARL write-up say further work on additional lab markers and on generic rapamycin, which has higher bioavailability, will shape any future protocol for extending healthspan.
