What is the optimal amount of spermidine? Dosage recommendations from studies
Leila WehrhahnUpdated:Key points at a glance:
Most studies use around 0.9 to 1.2 mg of spermidine per day, typically from standardised wheat germ extract, over periods ranging from 3 to 12 months. Findings on cognitive aspects are mixed. Spermidine can also be obtained from foods such as soybeans, peas, mushrooms, wheat germ and aged cheese. It is generally recommended to start with a lower amount and gradually increase, provided it is well tolerated. Overall, safety has been described as good in the available research. Short-term intakes of up to 40 mg have been reported as tolerable, but this does not constitute a dosage recommendation. It is important to check how many milligrams of spermidine are contained per serving and to discuss potential risks with a healthcare professional.
What is spermidine – and why are longevity researchers interested in it?
Spermidine is a naturally occurring polyamine found in many everyday foods, especially plant foods. Inside our cells, it helps maintain normal cellular function and is involved in processes such as cell growth, repair and general homeostasis.
In recent years, spermidine has attracted attention in the longevity field. Human studies have mainly explored:
- Memory and cognitive function in older adults
- Long-term links between dietary spermidine intake and mortality
- Cardiometabolic markers and cardiovascular risk
Results are encouraging but mixed. Randomised trials using wheat germ extract show small or no cognitive benefits overall, while large cohort studies report associations between higher spermidine intake and lower mortality or cardiovascular disease. Laboratory work often discusses mechanisms such as “autophagy”, but these should be seen as background biology, not health promises.
Spermidine is a normal part of the diet. Studies focus on memory in older adults and long-term health associations. It is scientifically interesting, but not a miracle anti-ageing pill.
Spermidine Capsules
How do human studies dose spermidine?
Overview of spermidine dosage in human trials
| Population | Study type | Form | Daily dose (mg spermidine) | Duration | Primary endpoints | Safety | Year/country |
|---|---|---|---|---|---|---|---|
| Older adults with subjective cognitive decline (SCD) | RCT, double-blind (Phase IIa) | Standardised wheat germ extract | 1.2 | 3 months | Mnemonic Similarity Task; moderate improvement vs placebo | Well tolerated | 2018, DE Cortex paper, Safety |
| Older adults with SCD | RCT, double-blind (SmartAge, Phase IIb) | Standardised wheat germ extract | 0.9 | 12 months | No significant difference vs placebo (primary outcome); exploratory signals (verbal memory, inflammation) | Adverse events balanced between groups | 2022, DE JAMA Network Open |
| Care home residents (mild–moderate dementia) | Randomised, double-blind, 2 active doses (no placebo) | Baked goods with wheat germ/bran | ≈ 1.9 vs 3.3 mg per roll, 6×/week (average daily increase ≈ 20–35%) | 3 months | CERAD/MMSE: dose trend in favour of higher dose | Well tolerated | 2020/2021, AT Wien Klin Wochenschr |
| Healthy men (50–70 years) | RCT, double-blind, crossover (safety/PK) | Pure spermidine trihydrochloride | 40 | 7 and 28 days | Safety/polyamine kinetics | No safety-relevant changes vs placebo | 2024, USA Nutrients (online ahead) |
| General population | Prospective cohorts (dietary FFQ) | Dietary intake (estimated) | Tertiles: <~9 vs ~9–11.6 vs >~11.6 mg/day (converted from μmol) | 20 years follow-up | Higher intake associated with lower mortality and cardiovascular disease (CVD) risk | Observational (no causality) | 2018, IT/AT AJCN, Nat. Commun. supplement |
What do these spermidine doses mean in real life?
- If your product is standardised to spermidine (for example 0.75–2.0 mg spermidine per capsule), the study-like dosage of around 0.9–1.2 mg/day usually equates to about 1–2 capsules per day. Always check the label for “mg spermidine per serving”.
- Label check: If the label only states something like “750 mg wheat germ extract”, the actual spermidine content should also be declared. In one study, 750 mg extract contained about 0.9 mg spermidine. Protocol details.
- Dietary benchmark: In the Bruneck cohort, the highest intake group consumed >~11.6 mg/day of spermidine from food alone. This level is achievable with a polyamine-rich diet (see below), but not necessarily every day.
Most clinical trials use about 1 mg spermidine per day from a standardised extract. You can also significantly increase intake via foods such as soya, peas, mushrooms, wheat germ and mature cheese.
Diet first: how to get spermidine from food before using a supplement
If you are health-conscious and cautious about supplements, it is reasonable to start with diet and only consider a spermidine supplement if needed. A more detailed discussion is here: Spermidine – diet vs supplement.
Top spermidine food sources (practical shopping list)
Spermidine levels vary by variety, ripeness and processing. The values below (mg per 100 g and per typical serving) are based on a validated food database and reviews.
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Wheat germ: ~22–34 mg/100 g
Typical serving: 10 g as a topping → ≈ 2.2–3.4 mg -
Cooked soya beans: ≈ 5.1 mg/100 g
Serving: 190 g → ≈ 9.7 mg Portion table -
Green peas: ≈ 3.3–6.5 mg/100 g
Serving: 140 g → ≈ 9.1 mg -
Mushrooms (e.g. button mushrooms): ≈ 8.9 mg/100 g
Serving: 50 g → ≈ 4.4 mg -
Broccoli: ≈ 3.6 mg/100 g
Serving: 100 g → ≈ 3.6 mg - Mature cheese: highly variable; some blue cheeses reach ≈ 10 mg/100 g (with a few much higher), many everyday hard cheeses are lower.
Three simple day-to-day ideas:
- Yoghurt or skyr with 10 g wheat germ and a soya-based granola
- Wholegrain bread with mature cheese plus a mixed mushroom side salad
- Tofu and mushroom stir-fry with peas and broccoli
When might a spermidine supplement be reasonable?
- If your normal diet rarely includes soya, pulses, mushrooms or wheat germ, and you do not reach your target intake from food alone.
- If your doctor or nutrition professional suggests a standardised spermidine supplement with a clearly defined dosage.
- When choosing a product, look for:
- Standardisation to spermidine (mg stated)
- Batch testing with a certificate of analysis (CoA)
- Mycotoxin screening for wheat-based products
- Clear allergen information (gluten/barley/wheat) and vegan capsules if required
Practical spermidine dosage: an evidence-informed approach
New to spermidine? How to introduce it cautiously
For many health-conscious adults, a “start low, go slow” approach is sensible:
- Weeks 1–2: 0.5–0.75 mg/day (with a meal). Notice how your digestion, sleep and energy feel.
- Weeks 3–8: If well tolerated, increase towards 0.9–1.2 mg/day, in line with study-like intake.
- Every 8–12 weeks: Review how you feel. If agreed with your doctor, you may also monitor objective markers such as blood pressure, lipid profile or inflammatory markers.
When to take spermidine? Trials do not show a clear advantage for taking spermidine on an empty stomach versus with food. In studies, intake was often spread over main meals (for example, 2 capsules with breakfast/lunch/dinner). Follow your product’s instructions.
Spermidine cycling vs continuous use
Most human randomised trials used continuous daily dosing for 3–12 months. There is currently no good human evidence that “cycling” (e.g. 5 days on, 2 days off) works better.
How spermidine fits with lifestyle and other longevity habits
- Sleep and movement: Regular exercise and good sleep are still the most robust longevity “interventions”. Supplements are an add-on, not a replacement.
- Balanced diet and protein: A diet rich in vegetables, wholegrains and adequate protein naturally contains polyamines and many other beneficial nutrients.
- Fasting and time-restricted eating: These are popular, but there are no robust human trials on combined effects of spermidine plus fasting. Be wary of mechanistic claims that have not been tested in people.
If you choose a spermidine supplement, start with a low dose and build towards the 0.9–1.2 mg/day range used in many trials, if suitable for you. Take it with meals and focus on consistency rather than complex “cycling” patterns.
Spermidine safety, contraindications and possible interactions
Spermidine dosage and safety should always be considered together, especially if you have existing conditions or take medication.
- General tolerability: Studies using 0.9–1.2 mg/day for 3–12 months report good overall tolerability. Side effects were uncommon and mainly mild digestive symptoms. SmartAge, 2018 safety data.
- Short-term high-dose data: A safety trial in older men used 40 mg/day of pure spermidine for up to 28 days without safety-relevant changes compared with placebo. This is not a recommended dose for self-use, but it does provide some reassurance about upper safety margins. Nutrients 2024.
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Seek medical advice before use if you:
- Are pregnant or breastfeeding
- Have active cancer or a history of hormone-sensitive tumours
- Have had an organ transplant or use immunosuppressive medicines
- Have severe liver or kidney impairment
- Are undergoing or planning chemotherapy or targeted cancer therapy
- Are older and on multiple medicines (polypharmacy)
- Polyamines and cell growth: Polyamines can support cell proliferation in general. For people with a history of cancer, spermidine use should be discussed individually with an oncology team. Observational studies on polyamines and cancer risk are mixed and cannot prove cause and effect.
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Product quality: Choose supplements with:
- GMP manufacturing
- A recent CoA confirming polyamine content
- Clear allergen labelling (especially gluten and wheat)
- Mycotoxin and, ideally, heavy metal screening
- Transparent declaration of “mg spermidine per serving”
- Regulatory status in the UK/EU: Spermidine products are regulated as food supplements, not as medicines. They are not intended to treat or prevent disease. Health claims must comply with EU/UK nutrition and health claims law. Specific claims such as spermidine “for hair growth” have been assessed and are not authorised.
How to choose a high-quality spermidine supplement
A curated overview of relevant products is available in the longevity collection.
- Clear labelling: The label should state the exact mg of spermidine per serving, not just “mg of wheat germ extract”.
- Standardisation and source: Look for a standardised wheat germ extract or a clearly described spermidine source (e.g. pure spermidine trihydrochloride).
- Manufacturing quality: GMP certification, batch testing, polyamine quantification, mycotoxin and heavy metal testing.
- Allergens and suitability: Clear information on gluten/wheat; vegan capsules if you prefer plant-based products.
- No “proprietary blends” hiding content: The active spermidine dosage should be fully transparent.
- Price per mg spermidine: For example: 30 capsules providing 1 mg each = 30 mg total. Divide the product price by 30 to get the cost per mg. Compare products on this basis and on quality, not just capsule count.
FAQ: common questions about spermidine dosage and use
Can I get enough spermidine from my diet alone?
With deliberate planning, often yes. A day that includes soya beans (around 190 g ≈ 9.7 mg), peas (around 140 g ≈ 9.1 mg) and some wheat germ as a topping can easily provide >10 mg. In practice, daily intake will fluctuate depending on what you eat.
Is a higher spermidine dosage always better?
Probably not. Many biological responses follow a U-shaped curve, where too little and too much may both be suboptimal. For now, staying close to study-like intakes of about 0.9–1.2 mg/day from supplements is a cautious, evidence-aligned option, if appropriate for you. Very high doses should be reserved for research settings or strict medical supervision.
How long before I notice anything?
Human cognitive studies lasted from around 8–12 weeks (pilot work) up to 12 months (SmartAge). Any changes in memory, energy or wellbeing are individual and not guaranteed.
Is spermidine suitable for older parents (70+)?
It may be considered, but in older adults with multiple medications, frailty or dementia, use should be discussed with a GP or specialist first. If used, start with a low dose and monitor tolerability carefully.
What is the difference between spermidine, spermine and putrescine?
All three are polyamines. In plant foods, spermidine is usually the dominant form. In animal foods, spermine tends to be more abundant. Food supplements typically focus on spermidine, as this is the compound most studied in relation to healthy ageing.
7-day plan: putting spermidine into practice safely
- Days 1–2: Review your normal meals. How often do you eat soya, pulses, mushrooms, wholegrains, wheat germ or mature cheese?
- Day 3: Decide whether to focus on a diet-first approach or to add a standardised spermidine supplement (checking the mg dosage).
- Days 4–7: Aim for around 0.5–0.75 mg/day from food plus, if using one, a supplement. Keep a brief log of digestion, sleep and energy.
- Weeks 2–8: If well tolerated, gradually move towards a 0.9–1.2 mg/day supplemental dosage (plus dietary intake), if suitable for you. Arrange a medical review, especially if you take regular medication.
Key takeaways on spermidine dosage and long-term health
- Typical study dosage: Around 0.9–1.2 mg spermidine per day from standardised wheat germ extract, taken continuously for 3–12 months in human trials.
- Diet contributes significantly: Soya, peas, mushrooms, wheat germ, broccoli and some cheeses can together provide daily intakes in the double-digit mg range.
- Consistency over extremes: Regular, moderate spermidine intake (from diet or diet plus supplement) is more in line with the evidence than occasional, very high doses.
- Generally good safety, but check individually: Extra caution is needed in cancer, post-transplant, with immunosuppression, in pregnancy/breastfeeding and in those on multiple medicines.
- Quality and labelling matter: Choose products that clearly state “mg spermidine per serving”, use standardised extracts, provide a CoA and screen for allergens and mycotoxins.
- Regulation: Spermidine supplements in the UK/EU are foods, not medicines. Unauthorised health claims (e.g. for disease treatment or hair growth) are not permitted.
Glossary
- Polyamines: Small, positively charged molecules (including spermidine, spermine and putrescine) that occur naturally in cells and foods and are involved in cell growth and function.
- Standardised extract: A plant extract in which the content of a specific active compound (such as spermidine) is defined and measured, for example “mg spermidine per g extract”.
- RCT (Randomised controlled trial): A study design in which participants are randomly allocated to different interventions (e.g. spermidine vs placebo) to test effects in a controlled way.
- Cohort study: An observational study that follows a group of people over time to examine associations between exposures (such as dietary spermidine) and outcomes (such as mortality), without proving causality.