A new two-part study found that psilocybin significantly extended lifespan and improved biological aging markers in mice and human cells. Aged mice (19 months old, ~60–65 human years) given psilocybin lived 30% longer than controls, with visible signs of healthier aging: better fur, fewer white hairs, and even hair regrowth. In the lab, human skin and lung cells treated with psilocin (psilocybin’s active form) lived over 50% longer, showing preserved telomeres, reduced oxidative stress, and improved DNA repair. These results offer the first direct support for the “psilocybin–telomere hypothesis,” suggesting psilocybin may slow aging by reducing cellular damage and preserving chromosome health.