Taking low doses of a drug called rapamycin once a week doesn’t seem to reduce belly fat in healthy older adults after nearly a year, whether they take 5 mg or 10 mg — it’s about the same as taking a dummy pill.

Taking a low weekly dose of a drug called rapamycin for a year might help older women build more lean muscle, which could slow down muscle loss as they age.

Taking a lot of rapamycin each week might make it harder for older people to build muscle from exercise, but a smaller dose could be better for strength and body health.

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.

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.

Giving old mice the drug rapamycin less often (every 5 days instead of daily) at a specific dose helps them live longer without causing diabetes-like problems, showing that we might be able to get the good anti-aging effects without the bad side effects.