Molecule
Spermidine
A polyamine your cells need to trigger autophagy. Found richly in wheat germ, aged cheese, and mushrooms. One of the more mechanistically clean longevity candidates.
Summary Can spermidine help slow ageing or support brain health? Show / hide ↓
Spermidine is a natural substance found in foods such as wheat germ, aged cheese, mushrooms, and soybeans. It may stimulate autophagy, the process cells use to recycle damaged parts. This process extends lifespan in several animals, but that does not prove it extends human life. In a large observational study, people with higher dietary intake were associated with living 5.7 years longer, although other lifestyle factors may explain part of this difference. A randomized trial of about 100 older adults over three months reported better cognition and biological markers, but larger and longer studies are needed. Getting about 10–15 mg a day from food appears feasible, while supplements commonly provide 1–5 mg.
What this means for you: Spermidine has promising biology and some encouraging human findings, but it is not proven to extend lifespan. Food sources are a reasonable option, while buying a supplement remains an individual choice rather than an evidence-based necessity.
early evidenceSpermidine acts through autophagy induction. Autophagy is how cells recycle damaged proteins and organelles, and it declines with age. Chronic autophagy stimulation extends lifespan in yeast, worms, flies, and mice. Spermidine is among the few dietary molecules with credible autophagy-inducing effects in humans at achievable doses.
Observational data in humans is notable. A large Austrian cohort (Bruneck study) found dietary spermidine intake in the top tertile associated with a 5.7 year longer life expectancy compared to the bottom tertile, independent of other diet factors. That is an unusually large effect for an observational nutrient study and should be treated with appropriate skepticism (residual confounding is possible), but the mechanistic backing gives it more weight than typical nutritional epidemiology.
Randomized human data is thinner. Small trials have shown mild cognitive benefits in older adults with subjective memory complaints. No large hard-endpoint RCTs exist.
Dietary sources contain substantial spermidine: wheat germ (highest, roughly 25 mg per 100 g), aged cheese, mushrooms, soybeans, corn. Achieving the observational intake range (roughly 10-15 mg/day) is feasible through diet alone. Supplements typically provide 1-5 mg/day of standardized wheat germ extract.
Safety is well established, spermidine is a normal dietary molecule at these doses.
2026 RCT: Spermidine Improves Cognition in Older Adults
A randomized, placebo-controlled trial published in JAMA Network Open found that spermidine supplementation improved cognition and biomarkers in older adults with subjective cognitive decline [1]. Approximately 100 participants received spermidine or placebo for 3 months. This is one of the few human RCTs for spermidine, which is primarily known from preclinical research showing lifespan extension in flies and worms. Spermidine is found naturally in wheat germ, aged cheese, mushrooms, and soy products.
Products with this: Spermidine
References
Every numbered citation in this entry links here. Each reference links out to the primary source.
Further reading
Curated external sources for a deeper dive. External links open in a new tab.