Is rapamycin found in food, or can you get it naturally through your diet?

Rapamycin is not found in food. It is a substance produced exclusively by a soil bacterium, Streptomyces hygroscopicus, originally discovered on Easter Island. You cannot obtain it through your diet: it is extracted in a laboratory via bacterial fermentation and then processed into a medicine.

Clinically, rapamycin is approved as a drug to prevent rejection after organ transplants. It inhibits a central regulatory protein in cells called mTOR, which controls cell growth and metabolism. By inhibiting that protein, rapamycin in a sense mimics the effects of caloric restriction, without requiring you to eat less. Multiple reviews describe this mechanism as biologically plausible.

In animal research, the effects on lifespan are striking: a meta-analysis of 167 studies across eight different vertebrate species found that rapamycin significantly extended lifespan, roughly comparable to what long-term caloric restriction achieves. There was, however, considerable variation between studies, and the data are susceptible to publication bias, meaning that studies with positive outcomes are published more often than negative ones.

For humans, conclusions of this kind cannot yet be drawn. The level of evidence in humans is limited. In addition, rapamycin carries a serious safety risk: it suppresses the immune system. That is why it is used as a medicine only under strict medical supervision. People who experiment with rapamycin outside a medical setting run a real risk of infections and other immune-related problems. No food, supplement, or herb exists that contains rapamycin or produces the same effect.