In 1678, the Dutch scientist Antonie van Leeuwenhoek peered through one of his handmade microscopes and noticed tiny crystals that no one had described before1. It took around 250 years for anyone to work out what they were, a compound later named spermine1.
Its close cousin, spermidine, has since become one of the most talked about names in healthy ageing. More and more people ask us about it after seeing a video about living longer, and the claims online, from cell renewal to thicker hair, can sound very convincing.
So can spermidine help you age well, and should you take it? Below we walk through what the studies in people show, the simplest place to start, and who should be especially careful, so you can make up your own mind.
What exactly is spermidine?
Spermidine is a natural compound called a polyamine, found in every living cell. Your body makes some itself, and the rest comes from foods such as wheat germ, mature cheese, mushrooms, soybeans and other legumes2.
Interest grew after research in cells and animals suggested it may encourage autophagy, the cell's natural recycling process3. Most spermidine supplements sold in the UK are made from wheat germ extract.
What do the studies in people actually show?
This is where the picture becomes less clear. Much of the excitement comes from mice and cell studies, while research in people is still limited and mixed3.
A long look at life in an alpine town
In Bruneck, a small town in South Tyrol in the Italian Alps, researchers followed 829 adults for around 20 years and kept a careful record of what they ate. Those whose everyday food was richer in spermidine had a lower risk of death during the study4.
That sounds impressive, but it was an observational study of food, not a trial of supplements. People who eat more wholegrains, legumes and vegetables tend to live differently in many other ways too.
What happened when older adults took a supplement?
The SmartAge trial in Germany gave 100 adults aged 60 to 90 either a spermidine supplement of around 0.9mg a day or a placebo, for 12 months. At the end, there was no meaningful difference in memory between the two groups5.
Memory is one of the most common reasons people look into supplements as they get older. If that is you, our post on lion's mane and memory looks at another natural ingredient we are often asked about.
What do the experts say overall?
A 2026 review in npj Aging concluded that spermidine is a promising candidate, but that its effectiveness in humans has not yet been established3. Germany's consumer advice centre, Verbraucherzentrale, puts it more plainly, saying no study has yet shown a benefit from spermidine supplements in healthy people2.
To be fair to spermidine, a lack of proof is not the same as proof that something does nothing. It does mean, though, that the confident claims online run well ahead of the evidence.
Does spermidine help hair growth?
Spermidine hair supplements have become popular, mostly because of one study. In a 2017 trial, 100 healthy adults took a spermidine based supplement or a placebo for 90 days6.
Those taking the supplement had more hair follicles in the active growth phase, called anagen6. The authors described their findings as preliminary, and the product contained other ingredients alongside spermidine.
Hair thinning can have many causes, so it is always worth speaking to your GP if you notice a change.
Where is the simplest place to start?
For most people, the kitchen is the simplest place to start. Some wheat germ supplements supply about 0.5mg of spermidine a day, which is roughly the same as 2.5g of cheddar or 50g of cooked cauliflower2.
A sprinkle of wheat germ on your porridge, a handful of mushrooms in a winter soup, a bowl of lentils or a little mature cheese all bring spermidine with them. Food also brings fibre, protein and many other nutrients that a capsule simply cannot.
If you are building a healthy ageing routine, our guide to herbs for healthy ageing shares the plants herbalists have long turned to. Many people also make room for omega 3 fats, and our Arctic Omega 3 is a whole food extract from Arctic herring roe, naturally rich in omega 3 phospholipids.
Is it safe to take spermidine every day?
Spermidine from ordinary food is considered safe2. For supplements, the short term picture looks reassuring, though there are some open questions.
What the trials found on side effects
In a three month pilot study, 30 older adults took 1.2mg of spermidine a day from wheat germ extract or a placebo. Researchers found no differences between the groups in vital signs, weight, blood tests or self reported health7.
In the 12 month SmartAge trial, adverse events were similar in both groups, and the serious ones were judged unrelated to the supplement5. The npj Aging review also noted that short term higher doses appeared safe in the trials it examined3.
The questions that remain
The German consumer advice centre notes that health risks from long term high intake cannot be ruled out, and that high doses may encourage the growth of some tumours2. A 2025 laboratory study in Japan also found that polyamines, including spermidine, raised levels of a protein linked with cancer cell growth8.
These findings come from cell studies and do not show that spermidine causes cancer in people. They are, however, a sensible reason for caution.
The same consumer centre reports that even 15mg a day did not raise spermidine levels in the blood2. So when it comes to spermidine, more is not necessarily better.
How much spermidine should I take?
We are not able to recommend a dose, and there is no official daily amount for spermidine. What we can share is what the rules and the research say.
In Great Britain, spermidine rich wheat germ extract is authorised as a novel food under reference NOVEL 130. It may only be used in food supplements for adults, not during pregnancy or breastfeeding, at up to the equivalent of 6mg of spermidine a day9.
The human trials we have described used much smaller amounts, around 0.9mg to 1.2mg a day5,7. Always follow the label and never take more than the stated amount.
Who should not take spermidine supplements?
Do not take spermidine supplements if you are pregnant or breastfeeding, or if you are under 18. They are not authorised for these groups in Great Britain9.
If you have cancer, or have had cancer in the past, do not take spermidine supplements unless your doctor has agreed. The German consumer advice centre specifically advises against them in this situation2.
Please also speak to your GP or pharmacist before trying spermidine if any of these apply to you.
- You take immunosuppressant medication2.
- You have coeliac disease or avoid gluten, because most products come from wheat germ.
- You take any regular medication or have a long term health condition.
You are also welcome to book a free 15 minute consultation with one of our herbalists. We are always happy to talk through your diet and whether a supplement makes sense for you.
Frequently asked questions
Should I take spermidine?
That depends on your health and your diet, and the evidence in healthy people is still limited2. Many people choose to focus on spermidine rich foods first and speak to a GP or pharmacist before trying a supplement.
Is it safe to take spermidine every day?
Short term trials of around 1mg a day found no difference in side effects compared with placebo5,7. Long term safety at high doses is less certain2.
How much spermidine should I take?
There is no official recommended amount. In Great Britain, supplements made from spermidine rich wheat germ extract are limited to the equivalent of 6mg of spermidine a day for adults9.
Does spermidine help hair growth?
One 2017 study of 100 adults found more hair follicles in the growth phase after 90 days6. The authors called the results preliminary.
What are the side effects of spermidine?
In the trials so far, side effects were similar to placebo5,7. Some experts urge caution at high doses because of questions about tumour growth2.
Is spermidine gluten free?
Not always, because most spermidine supplements are made from wheat germ. Check the label carefully, or ask your pharmacist if you have coeliac disease.
Which foods are highest in spermidine?
Wheat germ, soybeans and other legumes, mushrooms and mature cheese are among the richest everyday sources2. A varied diet built around wholegrains, beans and vegetables is the easiest way to include them.
References
- Bachrach, U. (2010). The early history of polyamine research. Plant Physiology and Biochemistry. huji.ac.il.
- Verbraucherzentrale (2026). Jung bleiben mit Spermidin, funktioniert das? Verbraucherzentrale. verbraucherzentrale.de.
- Jiang, Z. et al. (2026). Geroprotective insights into the natural metabolite spermidine in aging and age related diseases. npj Aging. nature.com.
- Kiechl, S. et al. (2018). Higher spermidine intake is linked to lower mortality: a prospective population based study. The American Journal of Clinical Nutrition. pubmed.ncbi.nlm.nih.gov.
- Schwarz, C. et al. (2022). Effects of spermidine supplementation on cognition and biomarkers in older adults with subjective cognitive decline: a randomized clinical trial. JAMA Network Open. ncbi.nlm.nih.gov.
- Rinaldi, F. et al. (2017). A spermidine based nutritional supplement prolongs the anagen phase of hair follicles in humans: a randomized, placebo controlled, double blind study. Dermatology Practical and Conceptual. dpcj.org.
- Schwarz, C. et al. (2018). Safety and tolerability of spermidine supplementation in mice and older adults with subjective cognitive decline. Aging. impactaging.com.
- Tokyo University of Science (2025). Polyamines stimulate the protein synthesis of the initiation factor eIF5A2 participating in mRNA decoding distinct from eIF5A1. Journal of Biological Chemistry. doi.org.
- Food Standards Agency (2020). Spermidine rich wheat germ extract (Triticum aestivum), NOVEL 130. Food Standards Agency. data.food.gov.uk.
