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Research · Supplements

Spermidine

In a 12-month trial in older adults with memory complaints, spermidine from wheat germ did not change memory or biomarkers. Doses of 15 and 40 mg a day did not raise blood spermidine. In one diet cohort, higher intake was linked to lower mortality. A larger cohort found a weaker pattern. Short trials found no adverse effects over placebo.

Add to Bio HackChecked 2026-11-09
Status
Dietary supplement in the US.
Also called
spermidine trihydrochloride, wheat germ extract, spermidineLIFE, polyamine, autophagy supplement
Taken for
slowing aging, longer life, autophagy, memory, brain health, immune aging, vaccine response, heart health, hair

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help3

Reported risks0

No risks sourced yet.

What people take it for, and what was found

Shown to help3

Limited

Immune aging and vaccine response

One small pilot found better immune markers and vaccine antibody response in adults over 65 who had not responded to a COVID-19 vaccine.

The numbers and sources
Effect
Over 13 weeks after a third COVID-19 vaccine dose, spermidine reversed markers of immune cell senescence and raised spike-specific IgG secretion, memory B cell recall and neutralizing antibody activity in people who had not responded to the vaccine [2].
Population
40 adults aged over 65, at 6 mg a day [2].
Sources
[2]
Caveats
A pilot study, and the effects were found in a subgroup of non-responders. TLL provided the product and part of the funding, and two authors consult for TLL [2].
Limited

Autophagy markers

One small pilot without placebo found autophagy markers rose at 3.3 mg a day over 8 weeks in healthy adults, but not at 1.5 mg.

The numbers and sources
Effect
After 8 weeks at 3.3 mg a day from a rice germ extract, blood Beclin-1 was 7.3% and ULK-1 13.4% higher than at baseline, BDNF 12.1% higher, and hs-CRP 20.8% and triglycerides 26.9% lower. The 1.5 mg dose did not show these changes [5].
Population
12 healthy adults, mean age 54.5, randomized to 1.5 or 3.3 mg a day [5].
Sources
[5]
Caveats
A single-blind pilot with no placebo group. Changes were measured against each person's own baseline. The trial tested one branded extract (Miricell, Nutraland USA) [5].
Limited

Longer life

Linked to longer life in people eating more spermidine in food, in two cohorts that differed in how strong the link was. Supplements were not tested.

The numbers and sources
Effect
Across thirds of dietary spermidine intake, deaths per 1,000 person-years were 40.5, 23.7 and 15.1. Each standard deviation of higher intake carried a hazard ratio for death of 0.74 (95% CI 0.66 to 0.83) [6]. In a cohort of 54,517 men, dietary spermidine showed a non-linear inverse pattern with all-cause mortality (p for non-linearity 0.10), which the authors say may reflect residual confounding. It was not linked to prostate cancer incidence (RR 1.00, 95% CI 0.89 to 1.12) [7].
Population
829 adults aged 45 to 84 in a community-based cohort, followed 1995 to 2015 with 341 deaths [6]; 54,517 men in the US PLCO screening trial [7].
Sources
[6], [7]
Caveats
Both are observational studies of spermidine from food, measured by questionnaire. Neither tested supplements. The two cohorts differ in how strong the link was.

Not shown to help2

Limited

Memory and cognition

One trial found no change in memory over 12 months in adults aged 60 to 90 with memory concerns, at a low dose.

The numbers and sources
Effect
Over 12 months, mnemonic discrimination did not differ from placebo (difference -0.03, 95% CI -0.11 to 0.05). Secondary outcomes also did not differ. Exploratory analyses suggested possible effects on inflammation and verbal memory [1].
Population
100 adults aged 60 to 90 with subjective cognitive decline, given 0.9 mg spermidine a day from wheat germ extract or placebo [1].
Sources
[1]
Caveats
One trial at a low dose. Three authors held equity in and advised The Longevity Labs (TLL), the extract's maker, and a fourth was its chief executive while the trial ran. TLL funded development of the extract [1].
Limited

Blood spermidine levels

Small trials found spermidine supplements did not raise blood spermidine levels in healthy adults, even at 40 mg a day.

The numbers and sources
Effect
At 15 mg a day for 5 days, plasma spermine rose against placebo, while spermidine and putrescine did not change [3]. At 40 mg a day for up to 28 days, serum and urine polyamines did not change substantially [4].
Population
12 healthy adults in a crossover trial [3]; 37 healthy men aged 50 to 70 [4].
Sources
[3], [4]
Caveats
Two small, short trials. The authors of [3] suggest spermidine is converted to spermine before reaching the blood. Two authors of [4] were employees of Chrysea Labs, the product's maker, which funded the other authors.

Doses studied

Trials used 0.9 mg a day from wheat germ extract for 12 months [1], 6 mg a day for 13 weeks [2], 15 mg a day for 5 days [3] and 40 mg a day of purified spermidine for up to 28 days [4]. A pilot compared 1.5 and 3.3 mg a day from rice germ extract for 8 weeks [5].

Risks

Checked, no increase found1

Limited

Adverse effects in trials

Small trials found adverse events about as common as on placebo for up to 12 months.

The numbers and sources
Effect
Adverse events were balanced between spermidine and placebo over 12 months [1]. At 40 mg a day for 28 days, clinical, lipid, chemistry and blood count measures did not change against placebo, and no product-related adverse events were reported [4]. A 13-week pilot reported the supplement was well tolerated [2].
Population
100 older adults [1]; 37 healthy men [4]; 40 older adults [2].
Sources
[1], [4], [2]
Caveats
Small trials of a year or less. Two of the three had maker involvement.

Possible, not studied in people1

UntestedHow often is not known

Long-term use

Not studied in people. Lifelong spermidine extended lifespan in mice, while lab and animal work links spermidine both to colorectal tumor growth and to protection.

No study in people. This rests on animal studies, lab studies, how it acts in the body.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Oral spermidine extended the lifespan of mice and reduced cardiac hypertrophy in old mice [8]. A 2026 review describes spermidine as a pro-tumor metabolite that sustains colorectal cancer growth through a MYC and eIF5A circuit, while other experiments found high doses killed cancer cells and spermidine protected against colitis-associated cancer [9]. Human trials located lasted up to 12 months [1].
Population
Mice and rats [8]. Cell and animal models of colorectal cancer, reviewed [9].
Sources
[8], [9], [1]
Caveats
Animal and lab findings point in different directions and do not show what years of supplement use do in people. No supplement trial longer than a year was located.

Claims tested and not found

  1. That spermidine improves memory in older adults. A 12-month trial found no change in memory performance against placebo [1].
  2. That spermidine supplements raise blood spermidine. Doses of 15 mg [3] and 40 mg [4] a day did not raise blood spermidine.
  3. That dietary spermidine lowers prostate cancer risk. Intake was not linked to prostate cancer incidence or prostate cancer death in 54,517 men [7].

Sources

  1. Schwarz C, Benson GS, Horn N, et al. Effects of Spermidine Supplementation on Cognition and Biomarkers in Older Adults With Subjective Cognitive Decline: A Randomized Clinical Trial. JAMA Network Open. 2022. https://doi.org/10.1001/jamanetworkopen.2022.13875
  2. Alsaleh G, Ali M, Kayvanjoo AH, et al. Spermidine Mitigates Immune Cell Senescence and Boosts Vaccine Responses in Healthy Older Adults. A Pilot Study. Aging Cell. 2026. https://doi.org/10.1111/acel.70545
  3. Senekowitsch S, Wietkamp E, Grimm M, et al. High-Dose Spermidine Supplementation Does Not Increase Spermidine Levels in Blood Plasma and Saliva of Healthy Adults: A Randomized Placebo-Controlled Pharmacokinetic and Metabolomic Study. Nutrients. 2023. https://doi.org/10.3390/nu15081852
  4. Keohane P, Everett JR, Pereira R, et al. Supplementation of spermidine at 40 mg/day has minimal effects on circulating polyamines: An exploratory double-blind randomized controlled trial in older men. Nutrition Research. 2024. https://doi.org/10.1016/j.nutres.2024.09.012
  5. Bruno G, La Monica M, Ziegenfuss TN. Effects of Spermidine-Rich Rice Germ Extract Supplement on Biomarkers of Healthy Aging and Autophagy-Proof-of-Concept Pilot Study. Alternative Therapies in Health and Medicine. 2025. https://pubmed.ncbi.nlm.nih.gov/40862848/
  6. Kiechl S, Pechlaner R, Willeit P, et al. Higher spermidine intake is linked to lower mortality: a prospective population-based study. The American Journal of Clinical Nutrition. 2018. https://doi.org/10.1093/ajcn/nqy102
  7. Wang G, Lin J, Lin Z, et al. Dietary spermidine intake is not associated with prostate cancer incidence or prostate cancer-specific mortality: findings from the prostate, lung, colorectal, and ovarian cancer screening trial. Frontiers in Nutrition. 2026. https://doi.org/10.3389/fnut.2026.1775582
  8. Eisenberg T, Abdellatif M, Schroeder S, et al. Cardioprotection and lifespan extension by the natural polyamine spermidine. Nature Medicine. 2016. https://doi.org/10.1038/nm.4222
  9. Coni S, Bordone R, Campea L, et al. Spermidine in Colorectal cancer: friend or foe? Amino Acids. 2026. https://doi.org/10.1007/s00726-026-03554-w

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