Rapamycin: The Drug That Extends Life in Every Species Tested

01 The mTOR Discovery

Rapamycin was discovered on Easter Island (Rapa Nui) in 1972, originally as an antifungal. In the 1990s, it was found to inhibit mTOR (mechanistic target of rapamycin), a protein that acts as a nutrient sensor and growth regulator. When mTOR is inhibited, cells shift from growth mode to repair mode. This is the same pathway activated by caloric restriction — the most robust lifespan intervention known. Rapamycin essentially tricks the body into thinking it's fasting.

02 The Species Data

Rapamycin extends lifespan in every species tested: 25% in yeast, 23% in C. elegans, 14% in fruit flies, 26% in female mice, 18% in male mice, and 28% in dogs. No other drug has this breadth of efficacy. The mouse data is particularly striking — rapamycin extends life even when started late in life (equivalent to starting at age 60 in humans). This is the dog bite-size trials at the University of Washington — companion dogs living normal lives, given rapamycin, and living measurably longer.

03 The Human Trial

The TAME (Targeting Aging with Metformin) trial was the first FDA-approved trial targeting aging itself as an endpoint. It uses metformin, not rapamycin, but it establishes the regulatory pathway. Rapamycin human trials are now beginning: one at the Buck Institute for aging biomarkers, another for immune system rejuvenation in elderly adults. The key question isn't whether rapamycin works in humans — it's whether the side effects (immunosuppression at high doses, wound healing issues) are manageable at anti-aging doses.