Spermidine
What’s New This Month
- Recall: FDA classed a 2025 recall of Dorado Nutrition Spermidine Maximum Strength 10 mg, sold on Amazon, as Class I for undeclared wheat. It ended in September 2025. 1
- FDA: In April 2025, FDA told one importer that its notification for synthetic spermidine trihydrochloride was incomplete. 2
- Pending trial: POLYCAD, a heart-disease trial of 187 people, finished in June 2026. No results are posted. 3
- Dose limit: The EU Union list sets a maximum of 6 mg a day of spermidine for wheat-germ extract. 4
Overview
Spermidine is a polyamine, a small molecule the body makes and also gets from foods such as wheat germ, soybeans, mushrooms, legumes and aged cheese. Supplements are mostly wheat-germ extract or a lab-made salt. 4 2
Its chemical family was first seen in 1678, when Antonie van Leeuwenhoek found crystals in semen; spermidine was first made in a lab in 1924. 5
Sellers claim it slows aging, renews cells, sharpens the brain and helps energy, the heart, hair, skin and nails.
How We Researched It
We rate each marketing claim with a modified version of GRADE, the system medical researchers use to say how sure we can be (i.e., high, moderate, low or very low), and check each trial with the Cochrane risk-of-bias tool, which asks whether a study’s design could skew its results. We used 28 records and read 22 seller pages. We checked FDA, California Prop 65, and regulators in Canada, Europe, the UK, Australia and Asia. Some Asian databases could not be read.
Research NotesTop three benefits
Hair GRADE: Very Low
In 100 healthy adults, a “spermidine-based” tablet for 90 days raised growing-phase hair follicles (+12.8 vs −5.3 on placebo). 6
Bias check: The maker, Giuliani S.p.A., funded the trial, and the tablet’s other ingredients and dose were not stated. Europe rejected the maker’s hair claim. 7
Healthy Aging GRADE: Very Low
No supplement trial has measured aging or survival. Diet studies disagree: in 829 people, higher intake went with 39% lower death rates, 8 but a Japanese study of 29,079 found no link. 9
Bias check: These studies measured food, not capsules. Three authors of the positive study own shares in a spermidine brand.
Energy GRADE: Very Low
No human trial has measured energy, fatigue, exercise capacity or mitochondria after spermidine.
Bias check: Claims rest on animal and cell studies.
Benefit Evaluation
| Claim | Claim Verdict | Research Confidence | Supporting Evidence | Safety Risk | Product Quality | FactStack™ Rating |
|---|---|---|---|---|---|---|
| Hair | Promising | Very Low | Promising | Caution | Inconsistent | Caution |
| Healthy Aging | TBD | Very Low | TBD | Caution | Inconsistent | Warning |
| Energy | TBD | Very Low | TBD | Caution | Inconsistent | Warning |
| Heart Health | TBD | Very Low | TBD | Caution | Inconsistent | Warning |
| Skin | TBD | Very Low | TBD | Caution | Inconsistent | Warning |
| Nails | TBD | Very Low | TBD | Caution | Inconsistent | Warning |
| Telomeres | TBD | Very Low | TBD | Caution | Inconsistent | Warning |
| Metabolism, Sleep, Antioxidant and NAD+ | TBD | Very Low | TBD | Caution | Inconsistent | Warning |
| DNA, Stress Response, Cell Membrane, Gut and Fasting Mimetic | TBD | Very Low | TBD | Caution | Inconsistent | Warning |
| Autophagy and Cellular Renewal | Doubtful | Very Low | Doubtful | Caution | Inconsistent | Warning |
| Cognition | Doubtful | Low | Doubtful | Caution | Inconsistent | Warning |
What Sellers Say vs. What Studies Show
| “It replenishes your spermidine.” | In three trials, 1.2 to 40 mg a day did not raise blood spermidine more than placebo. 10 11 12 |
| “It sharpens memory.” | The largest trial, 100 older adults for 12 months, found no memory benefit. 13 |
| “It makes you 5.7 years younger.” | That figure compared death risk by diet in 829 people. It is not about capsules, and three authors own shares in a spermidine brand. 8 |
| “It boosts autophagy, your cells’ cleanup.” | The largest trial did not measure autophagy. 13 |
| “It boosts nail growth 400%.” | No source was given, and no human nail trial exists. |
| “It is proven for heart health.” | No human trial has reported a heart outcome. The first, POLYCAD, has no results posted. 3 |
Trial ParametersIf you try it
| Who | Healthy adults who accept an unproven product. Not for pregnancy, breastfeeding or anyone under 18. |
| Dose | If trying it, stay at or under 6 mg of spermidine a day. 10 mg of the lab-made salt is about 5.7 mg. |
| Ceiling | EU maximum of 6 mg spermidine a day for wheat-germ extract, adults only. 4 |
| Duration | No data beyond 12 months. No stop rule established. |
| Form | Wheat-germ forms contain wheat and gluten; a Class I recall was for undeclared wheat. 1 |
| Ask First | Cancer or past colon polyps; DFMO; B12 deficiency; serious infection; heart failure; diabetes; coeliac disease; trying to conceive. |
How to Take It
| Pick a plan | Not reported. If you try it, stay at or under 6 mg a day, the EU limit. 4 |
| Time of day | Not reported. |
| With food | Not reported. |
| What to expect | No proven benefit. The 12-month memory trial found no change. 13 |
| How to take | Check the label: 10 mg spermidine trihydrochloride is about 5.7 mg of spermidine. |
Works With / Don’t Mix With
✓ Works with
Not reported. We found no supplement shown to add to spermidine’s effect.
Food. The studies that linked spermidine to longer life measured food within an overall diet, not capsules. 8
⚠ Ask first / don’t mix
DFMO, a colon-polyp drug. In one trial, high polyamine intake from food cancelled the drug’s benefit. 14
Cancer or past colon polyps. Tumors use polyamines, and high intake was linked to polyps coming back. 15
Coeliac disease or wheat allergy. Wheat-germ products contain wheat and gluten. 1
Pregnancy, B12 deficiency, infection, heart failure, diabetes. Health Canada’s licence record for one NMN-plus-spermidine product lists these cautions. 16
Manufacturer Recalls & WarningsLast 36 months, newest first
| Date | Maker / Brand | Product | Action | Src |
|---|---|---|---|---|
| Apr 2025 | Dorado Nutrition | Spermidine Maximum Strength 10 mg | FDA Class I recall: undeclared wheat; capsules sold on Amazon; ended Sep 2025. | 1 |
| Apr 2025 | Malaga Imports (Probase Nutrition) | Synthetic spermidine trihydrochloride, 10 mg a day | FDA told the importer its new-ingredient notification was incomplete. | 2 |
Where to Buy
We compare products side-by-side not just on price, but on whether NSF lists the product as NSF/ANSI 173 Contents Certified (an independent lab confirms the label matches the contents), whether it is NSF Certified for Sport, whether USP lists it as USP Verified, and whether the seller says it is manufactured in the USA. We leave out a brand’s products for this supplement when, in the last 36 months, the FDA took action against that brand over this supplement (a Class I or II recall, a warning letter, an import alert or an advisory letter). We also leave out any brand with an FDA Class II recall or warning letter on any product. We also leave out any product named in a California Prop 65 notice or a non-US recall, along with that brand’s products of the same ingredient and form. Brands with other actions stay listed and are marked in the Recall Screen column. Our goal remains to provide you, the Consumer, with the information and data necessary to make an informed purchasing decision. Prices reflected below are static and subject to change.
Ratings above describe the ingredient’s research, not any product listed below.
| # | Retailer | Product | Price | NSF 173 | NSF Sport | USP | Mfg. in USA (per seller) | Recall Screen | Affiliate link |
|---|---|---|---|---|---|---|---|---|---|
| 1 | iHerb | Neurogan Health, Spermidine, 10 mg, 120 Tablets | $24.95 | ✓ | ✓ | View on iHerb ↗ | |||
| 2 | iHerb | Codeage, Spermidine, 30 Vegetable Capsules | $24.99 | ✓ | ✓* | View on iHerb ↗ | |||
| 3 | iHerb | Force Factor, Spermidine, 120 Vegetable Capsules (5 mg per Capsule) | $25.73 | ✓ | ✓* | View on iHerb ↗ | |||
| 4 | iHerb | Nutricost, Spermidine Wheat Germ, 120 Capsules | $47.25 | ✓ | ✓* | View on iHerb ↗ | |||
| 5 | iHerb | Toniiq, Spermidine, 120 Capsules, (2.5 mg per Capsule) | $63.96 | ✓ | ✓ | View on iHerb ↗ |
Sources
1. Recall F-0729-2025: Dorado Nutrition Spermidine Maximum Strength 10 mg, undeclared wheat (Class I). US Food and Drug Administration (openFDA), 2025. api.fda.gov/food/enforcement.json?search=recall_number.exact:%22F-0729-2025%22
2. FDA letter on new dietary ingredient notification, report number 1392 (spermidine trihydrochloride). US Food and Drug Administration, 15 Apr 2025. downloads.regulations.gov/FDA-2025-S-0023-0044/attachment_1.pdf
3. POLYCAD: spermidine in coronary artery disease (187 people), trial record NCT06186102. ClinicalTrials.gov, 2026. clinicaltrials.gov/study/NCT06186102
4. Commission Implementing Regulation (EU) 2017/2470, Union list of novel foods, consolidated 10 Jan 2024 (spermidine-rich wheat germ extract). European Commission (EUR-Lex), 10 Jan 2024. eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:02017R2470-20240110
5. Bachrach U. The early history of polyamine research. Plant Physiology and Biochemistry 48(7):490–495, 2010. doi.org/10.1016/j.plaphy.2010.02.003
6. Rinaldi F et al. A spermidine-based nutritional supplement and hair growth, 90-day trial (100 adults). Dermatology Practical & Conceptual, 2017. doi.org/10.5826/dpc.0704a05
7. Scientific opinion on a spermidine-based health claim for hair (Giuliani). European Food Safety Authority (EFSA), 2011. doi.org/10.2903/j.efsa.2011.2466
8. Kiechl S et al. Higher spermidine intake and lower death rates, Bruneck cohort (829 adults). American Journal of Clinical Nutrition, 2018. doi.org/10.1093/ajcn/nqy102
9. Nagata C et al. Dietary polyamine intake and death in the Takayama cohort (29,079 adults). British Journal of Nutrition, 2024. doi.org/10.1017/S0007114523002465
10. Schwarz C et al. Safety and tolerability of spermidine in older adults, 3-month trial (30 adults). Aging, 2018. doi.org/10.18632/aging.101354
11. Senekowitsch S et al. Spermidine 15 mg a day and blood and saliva polyamines, crossover trial (12 adults). Nutrients, 2023. doi.org/10.3390/nu15081852
12. Keohane P et al. Synthetic spermidine 40 mg a day in men aged 50 to 70, 28-day trial (37 men). Nutrition Research, 2024. doi.org/10.1016/j.nutres.2024.09.012
13. Schwarz C et al. Spermidine and memory in older adults with subjective cognitive decline, 12-month trial (SmartAge, 100 adults). JAMA Network Open, 2022. doi.org/10.1001/jamanetworkopen.2022.13875
14. Raj KP et al. Dietary polyamines and the DFMO plus sulindac colon-polyp trial, secondary analysis. British Journal of Cancer, 2013. pubmed.ncbi.nlm.nih.gov/23340449/
15. Vargas AJ et al. Dietary polyamine intake and colorectal adenoma recurrence (1,164 people). American Journal of Clinical Nutrition, 2012. pubmed.ncbi.nlm.nih.gov/22648715/
16. Licensed Natural Health Products Database, licence 80122939. Health Canada, 23 Nov 2023. health-products.canada.ca/lnhpd-bdpsnh/info?licence=80122939
17. FDA warning letters database. US Food and Drug Administration, 6 Oct 2026. www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/compliance-actions-and-activities/warning-letters
18. openFDA food adverse event (CAERS) data. US Food and Drug Administration (openFDA), 7 Jul 2026. open.fda.gov/apis/food/event/
19. Recalls and safety alerts search, Health Canada. Health Canada, 9 Oct 2026. recalls-rappels.canada.ca/en/search/site?search_api_fulltext=spermidine&archive=1
20. Import Alert 54-18. US Food and Drug Administration, 27 Jun 2025. www.accessdata.fda.gov/cms_ia/importalert_1158.html
21. Import Alert 54-14. US Food and Drug Administration, 21 Sep 2026. www.accessdata.fda.gov/cms_ia/importalert_741.html
22. Import Alert 54-16. US Food and Drug Administration, 14 Aug 2026. www.accessdata.fda.gov/cms_ia/importalert_1141.html
23. ARTG entry 521098 (listed medicine containing spermidine). Therapeutic Goods Administration (Australia), 1 Dec 2025. www.tga.gov.au/resources/artg/521098
