Rapamycin's first big test on human lifespan came back flat

In the United States, 11,474 adults who received a kidney transplant between 2000 and 2007 and still had a working graft a year later and met the study's treatment criteria were split by one detail of their anti-rejection treatment: 4,885 were taking rapamycin (sirolimus), 6,589 were not. Researchers from NYU Langone Health and the University of Illinois Chicago followed them in the national transplant registry for a median of about 11 years, during which 6,443 died. On 5 November they reported in GeroScience that, once the two groups were made comparable, the median age at death was practically the same: 64.6 years with rapamycin and 64.3 years without.

No human trial of lifespan exists, so a registry stands in for one

Rapamycin is the drug with the most consistent record of extending life in mice: in a 2009 study in Nature it lengthened the lives of genetically diverse mice even when feeding started late in life. Since then it has become one of the most discussed candidates for slowing ageing in people, and some adults take it off-label for that purpose. A trial with lifespan as its endpoint would take decades, and none has been run. The drug, however, was first approved in the United States in 1999 for kidney transplant recipients, so the transplant registry holds years of continuous use in thousands of people, with deaths checked against external records. The authors describe their analysis as exploratory: a search for any signal that blocking the mTOR pathway changes human lifespan.

The raw gap vanished once the groups were made comparable

Before adjustment, the groups were not alike. People on rapamycin were nearly four years younger (median 48.0 versus 51.9), more often had a kidney from a living donor (46.7% versus 39.2%), had a slightly lower body mass index and were more often on cyclosporine rather than tacrolimus. Raw survival curves pointed in opposite directions depending on how time was counted: by age, people not on the drug reached a median age at death 2.9 years higher; counted from the first anniversary of the transplant, people on the drug lived a median of 1.9 years longer.

The authors weighted the groups on 18 factors, including age, body mass index, diabetes, donor type, transplant year, the rest of the immunosuppressive regimen and complications in the first year. After that, neither gap held. In the main analysis, which stopped counting at graft failure, the median age at death was 66.1 years on rapamycin and 66.7 years without (difference −0.6 years, 95% confidence interval −2.4 to 0.8). Following everyone to the end of 2025 regardless of the graft, it was 64.6 versus 64.3 years (difference 0.3, −1.6 to 2.0). The result was the same separately in patients on cyclosporine and on tacrolimus, and in two sensitivity analyses.

The drug was not a one-off: in years two to five after transplant, rapamycin was listed at 75% of annual visits in the rapamycin group and at 3% in the comparison group. Among deaths with a recorded cause, cardiovascular deaths made up a similar share, 29.5% and 28.5%, but the cause was missing for more than half of all deaths.

Transplant patients on daily dosing are not healthy adults

Everyone here had lived through kidney failure and a transplant and was taking several immunosuppressants at once. The authors themselves write that it is unclear whether a null result in this group carries over to healthy adults. Transplant care uses regular daily doses to keep blood levels stable, while people taking rapamycin for longevity usually take low, intermittent doses, often once a week, and the effect may differ. The authors add one counterpoint: in the key mouse studies, the daily doses that lengthened life were as high as or higher than those used to prevent rejection in mouse transplant models.

The design sets its own limits. This is an observational analysis, so factors the registry does not capture, such as past cancer, infection risk, protein in the urine or a centre's habits, could have steered who received the drug. Exposure was defined by the first year after transplant, and the registry recorded neither doses nor adherence. The study received no funding; the authors report consulting for transplant drug companies, unrelated to this work.

The small placebo-controlled trials point the same way

The authors set their result beside recent randomised trials in people who were not transplant recipients. In PEARL, 48 weeks of low-dose weekly rapamycin in healthy adults did not change visceral fat, the main outcome, and blood markers stayed within normal ranges; a few secondary measures improved in subgroups: lean mass and pain in women on the higher of two doses, self-rated emotional well-being and general health on the lower one. That trial was run by AgelessRx, a company whose employees wrote the paper. In RAPA-EX-01, 40 sedentary adults aged 65 to 85 followed a 13-week home exercise programme with weekly rapamycin or placebo. Both groups got stronger at chair stands; the drug did not add to the gain, sensitivity analyses favoured placebo, and adverse events were more frequent with rapamycin (99 versus 63), including one possibly drug-related case of pneumonia.

The decisive data will come from dogs before people

The Dog Aging Project's TRIAD trial is testing rapamycin against placebo in healthy middle-aged companion dogs and is meant to give the first lifespan evidence in a large animal. The authors' own conclusion is plain: at present, using rapamycin for longevity is not supported by evidence and awaits prospective trials in dogs and in people, with different dosing. Rapamycin is a prescription immunosuppressant, so anyone weighing it should discuss it with a doctor.

This material is for information only and does not replace a consultation with a doctor.

Sources

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• Harrison DE, Strong R, Sharp ZD, et al. Rapamycin fed late in life extends lifespan in genetically heterogeneous mice. Nature. 2009. PMID 19587680

• Moel M, Harinath G, Lee V, et al. Influence of rapamycin on safety and healthspan metrics after one year: PEARL trial results. Aging (Albany NY). 2025. PMID 40188830

• Stanfield B, Leroux B, Kaeberlein M, et al. Exercise and weekly sirolimus (rapamycin) in older adults: RAPA-EX-01 randomised, double-blind, placebo-controlled trial. J Cachexia Sarcopenia Muscle. 2026. PMID 41985884

• Coleman AE, Creevy KE, Anderson R, et al. Test of Rapamycin in Aging Dogs (TRIAD): study design and rationale. GeroScience. 2025. PMID 39951177