Guides · Spermidine

Spermidine: autophagy, longevity claims and what the human trials found

Spermidine is a natural polyamine that triggers autophagy, the cell's recycling system. It extends lifespan in yeast, flies, worms and mice, and people who eat more of it had lower mortality in an Austrian cohort study. That is an association, not proof. When it was tested as a supplement, a 3-month pilot hinted at better memory, but the larger 12-month SmartAge trial found no effect on memory or biomarkers at the dose used. Spermidine is interesting science with thin human evidence.

Written by The Bioregulator Atlas editorial team · Medical review pending · Facts and prices checked Oct 7, 2026

Animal lifespan
Extended in yeast, flies, worms (2009) and mice (2016)(source)
Observational (829 people)
HR 0.74 for all-cause death per 1-SD higher dietary intake(source)
SmartAge RCT (12 months)
0.9 mg/day: no change in memory or biomarkers vs placebo(source)
Pilot RCT (3 months)
30 older adults: moderate memory improvement (effect-size analysis)(source)

What spermidine is and why it got attention

Spermidine is a natural polyamine made in the body and found in food; the supplement in the largest trial was extracted from wheat germ. Researchers showed in 2009 that it induces autophagy and extends lifespan in yeast, flies and worms, and in 2016 that oral spermidine extended lifespan in mice and protected the aging heart.

Diet and mortality: an association

In the Bruneck study, 829 people aged 45 to 84 were followed from 1995 to 2015. Those with higher spermidine intake from food had lower all-cause mortality (hazard ratio 0.74 per standard deviation, 0.76 after more adjustment), and the finding was replicated in a second cohort. Diet studies like this cannot rule out that spermidine-rich diets are simply healthier diets.

Supplement trials in people

Pilot (2018): 30 cognitively healthy adults aged 60 to 80 with subjective memory complaints took a spermidine-rich plant extract or placebo for 3 months. Memory performance was moderately better in the spermidine group, but the study was small and was analyzed by effect sizes.

SmartAge (2022): the follow-up trial gave 100 people aged 60 to 90 a wheat-germ extract with 0.9 mg spermidine a day or placebo for 12 months. There was no significant change in memory or in secondary outcomes. Exploratory analyses hinted at effects on verbal memory and inflammation that the authors say need testing at higher doses. Three authors reported equity interests in and advisory roles for The Longevity Labs GmbH, and another was its chief executive while the trial ran.

Safety

In SmartAge, adverse events were balanced between spermidine and placebo over 12 months. Spermidine is a normal part of the diet, but concentrated supplements have only short-term safety data. Ask a clinician first if you are pregnant, have a chronic condition or take prescription medicines.

FAQ

What does spermidine do?

It triggers autophagy, the process cells use to break down and recycle worn-out parts. That is the proposed reason it extends lifespan in yeast, flies, worms and mice.

Do spermidine supplements improve memory?

Not in the best trial so far. A 3-month pilot suggested a benefit, but the 12-month SmartAge trial in 100 older adults found no change in memory at 0.9 mg a day.

Does spermidine help you live longer?

In animals, yes. In people, only an association exists: those who ate more spermidine had lower mortality in an observational study, which cannot prove cause and effect.

Is spermidine safe?

Adverse events were similar to placebo over 12 months in SmartAge. Longer-term data on concentrated supplements are lacking.

Do you earn money from this page?

No. This page has no paid links. We do not have an affiliate relationship with any brand that sells these supplements, so none is featured.

Related on the Atlas

Other guides: Epitalon vs Epithalamin · Bioregulators vs peptides · Thymalin vs thymosin alpha-1 · NMN vs NR vs NAD+ · Urolithin A · Rapamycin for longevity · Taurine and aging · Creatine for the brain · Magnesium for sleep · Melatonin for older adults · All health hubs

Not medical advice. Medical review pending: this page has not yet been reviewed by a licensed clinician. Statements about dietary supplements have not been evaluated by the Food and Drug Administration; these products are not intended to diagnose, treat, cure or prevent any disease. Compounded medicines are not FDA-approved. Prices change often; confirm on the seller's page.