Taking rapamycin, even in small doses now and then, might increase the chance of getting serious infections like pneumonia in older people because it can weaken the immune system.

Scientists have tested rapamycin in older people, but only to see if it helps the immune system fight infections. These studies look good, but they don't prove that rapamycin can help people live longer or healthier lives.

Scientists gave mice a drug called rapamycin when they were middle-aged (around 270 days old) and found that both male and female mice lived longer compared to mice that didn't get the drug.

Taking rapamycin once a week for a year might be safe for healthy older adults, with no more side effects than a sugar pill — so it could be a candidate for slowing normal aging.

Taking a low weekly dose of a drug called rapamycin for a year might make older adults feel healthier overall, based on their own reports.

Scientists are trying different ways to reduce the bad side effects of a drug called rapamycin—like giving lower doses, combining it with other medicines, or taking breaks between doses—and recent findings suggest that taking breaks might help keep the good effects while reducing the bad ones.