SpermidineNew

A naturally occurring polyamine found in wheat germ, natto, aged cheese, and other foods, spermidine is best known as a dietary trigger of autophagy — the cellular "clean-up" process that declines with age. Interest grew out of Frank Madeo's lab work showing spermidine extends lifespan in yeast, worms, flies, and mice, and epidemiological data linking higher dietary spermidine intake to lower cardiovascular and all-cause mortality in humans. Human trial evidence for supplementation itself is more mixed: the SmartAge trial (JAMA Network Open, 2022, n=100, 12 months) found spermidine-rich extract safe and well-tolerated in older adults with subjective cognitive decline but did not meet its primary cognitive endpoint, and a 2024 double-blind RCT found that 40 mg/day of oral spermidine had only minimal effects on circulating polyamine levels in older men, raising real questions about how much orally supplemented spermidine reaches target tissues. An ongoing Danish trial (POLYCAD) is testing spermidine in elderly coronary artery disease patients, with results expected in 2026. Given this, spermidine is a biologically plausible autophagy-support supplement with encouraging preclinical and observational data, but should be framed as promising rather than proven; discuss use with your physician, especially if you have cancer or a related condition.