Spermidine Dosage Calculator
A naturally occurring polyamine that declines with age. Induces autophagy — the cellular 'self-cleaning' process — and has extended lifespan across every model organism tested, including the first observational data in humans.
What is Spermidine?
Spermidine is an endogenous polyamine (a small polycationic molecule) found in all living cells, synthesised from putrescine via spermidine synthase. Intracellular and dietary spermidine levels decline significantly with age, paralleling the age-associated decline in autophagy — the lysosomal degradation system by which cells recycle damaged proteins and organelles. This connection is not coincidental: spermidine is one of the most potent endogenous inducers of autophagy identified to date. The landmark paper by Eisenberg et al. (Nature Medicine, 2016, PMID 27548521) demonstrated that spermidine supplementation extended lifespan in yeast, flies, worms, and aged mice, and reduced age-associated memory impairment in aged flies. Critically, the mechanism was autophagy-dependent — genetic ablation of autophagy genes abolished the lifespan-extending effect. In human epidemiological data, higher dietary spermidine intake (from spermidine-rich foods: wheat germ, aged cheese, mushrooms, soy) was associated with significantly reduced all-cause mortality over a 20-year follow-up in an Austrian cohort (Kiechl et al., BMJ, 2018). Spermidine's mechanism involves hypusination of eIF5A (a translation factor essential for autophagy gene expression), inhibition of EP300 acetyltransferase (which triggers autophagy when inhibited), and modulation of mitochondrial membrane potential. Beyond autophagy, spermidine has demonstrated anti-inflammatory effects (reducing IL-6, TNF-α), cardioprotection in aged mice (reversing diastolic dysfunction), and neuroprotective effects including improved memory consolidation in aged rodents and first-in-human data from a 2021 RCT (Wirth et al., Nutrients) showing improved memory performance in older adults with subjective cognitive decline.
How to Take Spermidine
**Dietary spermidine** (from wheat germ, aged cheese, mushrooms, natto, green peas) provides 5–15 mg/day in high-intake individuals — associated with the longevity benefits in observational studies. **Supplemental spermidine** (typically as spermidine trihydrochloride from wheat germ extract) provides a concentrated, standardised dose. **General longevity:** 1–5 mg/day spermidine from wheat germ extract. This matches the upper range of dietary intake in longevity-associated populations. **Anti-aging / cognitive support protocol:** 5–10 mg/day. The Wirth 2021 RCT used a wheat germ extract providing approximately 0.9–3.3 mg spermidine per day and showed cognitive benefits — suggesting high potency at modest absolute doses. Some longevity researchers use 10–15 mg/day; human safety data at these levels is limited but encouraging.
Timing Recommendations
Spermidine is ideally taken in a fasted state or with a light meal to maximise autophagy induction — a fasted metabolic state promotes autophagy synergistically. Morning dosing during intermittent fasting windows is the most pharmacologically rational approach. Spermidine and rapamycin share the mTOR suppression / autophagy pathway and are sometimes combined in longevity research contexts.
Potential Side Effects & Safety
Spermidine from wheat germ extract is very well tolerated in all completed human studies. GI effects (mild nausea, loose stools) occur occasionally at doses > 10 mg/day. Spermidine has polyamine-mediated cell growth-stimulating activity — theoretical concern in oncological contexts (see below). No drug interactions of clinical significance have been identified at supplemental doses.
Who should avoid Spermidine?
Active cancer: polyamines (spermidine, spermine, putrescine) are consumed by rapidly dividing cells and tumours often upregulate polyamine biosynthesis. Exogenous spermidine could theoretically support tumour growth; consult an oncologist. Wheat germ extracts contain gluten — coeliac disease patients should use purified spermidine HCl from a gluten-free source.
Best Stacks with Spermidine
Spermidine + fisetin for complementary senolytic and autophagic anti-aging mechanisms. Spermidine + NMN + resveratrol covers the three most evidence-supported longevity pathways: autophagy induction, NAD⁺/sirtuin axis, and caloric restriction mimicry. Time spermidine during fasting windows for maximum autophagy synergy.
Scientific References
All dosage recommendations are grounded in peer-reviewed research.
- 1Cardioprotection and lifespan extension by the natural polyamine spermidine
Nature Medicine · 2016
- 2Spermidine in health and disease
Science · 2018
- 3
Spermidine Dosage Calculator
Fixed dosage — independent of body weight
Your recommended daily dosage
Formula: 1–5 mg/day (longevity maintenance) | 5–10 mg/day (anti-aging protocol)
Safety notes
- Take in a fasted state or with a light meal to maximise autophagy induction.
- Coeliac disease: ensure your product is from a gluten-free source (not wheat germ).
- Active cancer patients must consult an oncologist — polyamines stimulate cell proliferation.
- No long-term human safety data above 10 mg/day.
This calculator provides general guidance only. Always consult a qualified healthcare professional before starting any supplement.