Spermidine
Polyamine that induces autophagy and declines with age; extends lifespan in model organisms.
Summary
Debbie explains that spermidine, a polyamine that drives autophagy, falls with age (though healthy centenarians have relatively high levels) and extends lifespan and healthspan by up to 25% in worms and mice, partly by protecting the heart. Human trials are small and mixed: some show cognitive benefit in mild dementia and longer hair growth phases, and one found no change at 1.2 mg/day over three months. Because putrescine is often the limiting factor, she highlights arginine plus a Bifidobacterium animalis subsp. lactis probiotic as a way to raise spermidine. She cautions that polyamines can feed tumor growth once cancer is present.
Calls it an excellent option for boosting autophagy, but hasn't tried wheat germ-based spermidine supplements because she doesn't eat wheat.From Spermidine and Healthspan
The evidence
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Human trial
In a double-blind study in nursing home residents, spermidine supplementation improved cognitive performance in those with mild dementia.
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Human trial
In a placebo-controlled human trial, three months of spermidine supplements prolonged the anagen (active growth) phase of hair.
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Human obs.
Older adults who ate more spermidine-rich foods had lower all-cause mortality and less heart disease.
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Animal
Spermidine supplementation has repeatedly extended lifespan and healthspan by up to 25% in model organisms, including C. elegans and mice.
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Animal
In mice, dietary spermidine lowered blood pressure and prevented age-related decline in heart function by preserving autophagy in cardiac muscle.
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Cell
Spermidine restored autophagy and function in T cells from older donors to levels similar to young donors' cells.
Read the study Discussed in Spermidine and Healthspan
Doses used in studies
Amounts reported in the research, not dosing recommendations.
| Dose | Context |
|---|---|
| 1.2 mg/day for three months | Older adults with cognitive decline; no difference, but safe and well-tolerated |
Cautions
- Spermidine cuts both ways in cancer: once a tumor grows, polyamines help it grow, and a polyamine-reduced diet helped in a prostate cancer trial.
- Fermented foods raise polyamines but also histamine, which is a problem for people with histamine intolerance.
- Studies in older adults suggest spermidine supplements are likely safe and well-tolerated; most are based on fermented wheat germ.
- SAMe, one precursor, can strongly affect mood; talk to your doctor before supplementing it if you have mood issues.