Spermidine and longevity

Spermidine is a small molecule called a polyamine that your body makes in almost every cell.^{[3, 9]} Your gut bacteria add some, and you eat more of it every day in foods such as wheat germ, soy and mushrooms.^{[3, 9]} The awkward name comes from semen: in 1678, Antonie van Leeuwenhoek saw crystals in human semen that were later named spermine, spermidine's close chemical cousin.^[9]

The name is history, though. Researchers care about the molecule because of autophagy, your cells' built-in recycling program for damaged proteins and worn-out parts (the full mechanism is in our autophagy guide). Autophagy slows down with age, so junk piles up inside cells and they work less well, and spermidine levels inside human cells fall with age too.^[1] Almost everything that extends life in animals, from eating less to rapamycin to exercise, turns autophagy back up. Spermidine does the same, and it needs working autophagy to do it.^[3] That is why researchers count it among the caloric restriction mimetics, substances that copy the benefits of eating less without the hunger.^[3]

That label rests on animal work from a Graz-led team. The team first showed that spermidine made yeast, worms and flies live longer, but only when their autophagy genes were intact.^[1] Seven years later it put spermidine in the drinking water of mice, which then lived longer and kept healthier hearts into old age.^[2] In mice whose heart muscle cells lacked a key autophagy gene, that heart protection did not appear.^[2]

Fasting put the same mechanism to a second test, since eating less is the classic way to turn autophagy up. A later study from the same group found that fasting raised spermidine in yeast, flies and mice and in the blood of human volunteers.^[10] Once the researchers blocked the polyamine pathway, fasting no longer extended lifespan in yeast, worms and flies.^[10] So spermidine looks like one of the molecules through which eating less pays off, at least in those animals.

Nearly all of this is animal and cell biology, and the mouse results are consistent, which is what makes spermidine a promising field. Whether they carry over to people is what the human studies are now testing, and most of those come from the same small research network.

Most spermidine research comes from one small network centered on the Frank Madeo lab at the University of Graz in Austria, part of the BioTechMed-Graz network. The animal studies, the fasting research, a review of the field and the SmartAge trial with Charité Berlin all trace back to this Graz group.^{[1, 2, 3, 8, 10]} That concentration matters, because a result repeated by the same network carries less weight than one repeated by an independent team.

The commercial side sits in Graz too. The only spermidine ingredient on the EU novel-food list is a wheat germ extract, notified in 2017 by Longevity Labs+.^[13] The Graz spin-off sells it as spermidineLIFE.^[13] The listing covers the ingredient, so other makers may sell extracts that meet the same specifications.^[12]

The researchers and the company are linked, and the papers disclose it openly. Several lead authors, Madeo among them, hold shares in Longevity Labs+ (legally TLL The Longevity Labs).^{[6, 8]} The company supplied the capsules for the Berlin safety trial,^[6] and its then CEO co-authored SmartAge.^[8] Ties like these are common in nutrition science and no scandal, but they are a reason to give independent results extra weight. The Wiener Neustadt nursing-home trial, for instance, was paid for by its own authors.^[7]

That self-funded trial came from FH Wiener Neustadt, a university of applied sciences south of Vienna.^[7] It is one of two other centers in the German-speaking world that have run human spermidine trials.^[7] The other is Charité Berlin, working with the German Center for Neurodegenerative Diseases (DZNE).^{[5, 8]} Together with Graz, those three ran almost every human trial up to 2022. The key diet study comes from the same region: the Bruneck cohort in South Tyrol, a German-speaking corner of northern Italy.^[4] Newer trials come from Germany, the UK and Denmark, plus one run by a maker of purified spermidine.^{[14, 15, 16, 17]} So the independent results that deserve extra weight are only now coming in.

Research in people offers an encouraging signal from food and an open question for capsules: more spermidine in the diet goes with a longer life, while the largest randomized trial with published results found no memory benefit.^{[4, 8]} The two results answer different questions, because one watched what people ate and the other tested a capsule against a placebo.

What diet studies show

The Bruneck Study followed 829 adults aged 45 to 84 in South Tyrol for two decades and estimated their spermidine intake from food questionnaires.^[4] People who ate more spermidine had a lower risk of dying from any cause, and each step up in intake, about the typical gap between two people, went with roughly a quarter lower risk.^[4] That link barely changed after the researchers accounted for smoking, weight, calories, exercise and other factors.^[4] Comparing the top third of intake with the bottom third, the difference in death risk was like being about 5.7 years younger.^[4] A second cohort near Salzburg showed the same pattern on its own.^[4]

The same Bruneck participants also supplied the heart findings. An earlier analysis, published alongside the mouse study, found that people who ate more spermidine had lower blood pressure and a lower risk of heart failure.^[2] They also had fewer cardiovascular events, a combined count of acute coronary events such as heart attacks, strokes and vascular deaths.^[2]

Like the death-risk finding, this is an association from one cohort, not proof.^[2] In Bruneck, most of it came from everyday plant foods eaten in quantity, such as whole grains, apples and pears, salad, sprouts and potatoes,^[4] so people who ate more of it may have eaten more healthily overall. In that case spermidine would partly be a marker of a healthy diet rather than the thing doing the work. Telling the two apart takes a randomized trial, in which chance decides who gets spermidine.

For the heart, such a trial has now finished. The Danish POLYCAD trial gave coronary patients aged 65 and over 24 mg of spermidine a day or a placebo.^[17] It measures heart muscle mass, fitness, muscle mass and an inflammation marker, not heart attacks or deaths. The trial ended in June 2026, but its results are not yet published (as of October 2026).^{[17, 23]}

What randomized trials show

For memory, a randomized trial has already reported: SmartAge, the largest one with published results.^[8] Its hundred participants were older adults with subjective cognitive decline, meaning they felt their memory slipping although standard tests still looked normal. For 12 months they took either a placebo or spermidine-rich wheat germ extract supplying about 0.9 mg of spermidine a day.^[8] The main test asked them to tell pictures they had seen before from very similar new ones. In the end, the trial found no measurable boost to memory and no change in the blood markers and most other measures.^[8]

SmartAge was also the larger test of an earlier pilot. That three-month trial in 30 people had found a medium-sized effect on memory discrimination, the ability to keep similar memories apart.^[5] The bigger, longer trial could not repeat it, which is exactly why pilots are followed by larger trials. And because everyone in SmartAge already worried about their memory, it cannot say whether spermidine prevents dementia in people with no symptoms yet.^[8]

Side results point to where the next trials are heading. Exploratory analyses hinted at benefits for inflammation and verbal memory.^[8] The authors want those tested at a higher dose, because the capsules raised daily spermidine intake by only about 10 percent.^[8] None of these hints would have survived the usual statistical correction for testing many outcomes at once, so they can only suggest ideas for new trials.^[8] A later brain scan analysis of the same trial found small differences in blood flow and white matter.^[20] Those differences did not track memory, and the authors call them preliminary.^[20]

Weaker signals from nursing homes

Outside SmartAge, the positive signals in people are weaker, and most of them come from six nursing homes in Styria, Austria. In a three-month double-blind trial there, 85 residents, most with some degree of dementia, ate breakfast rolls six days a week.^[7] The rolls were made with either wheat germ (3.3 mg spermidine per roll) or wheat bran (1.9 mg per roll).^[7] Because both kinds contained spermidine, there was no true placebo.^[7] Scores on the MMSE, a common dementia screening test, rose only in a small subgroup with mild dementia in the wheat germ group.^[7] Even that rise was measured against their own starting point, not against the other group.

The same team then followed 45 residents who got 3.3 mg a day with their food for a full year.^[18] Their MMSE scores rose by 5 points on average, but with no control group, normal ups and downs or simple practice with the test could explain that rise. These residents mostly had dementia already, unlike the worried but healthy SmartAge group. So the Styria results do not cancel SmartAge out; they only keep the question open for people who are already ill.

One more weak signal concerns the immune system. An Oxford pilot in 40 adults over 65 was built to test safety, and 6 mg a day for 13 weeks was well tolerated.^[16] In exploratory analyses, COVID vaccine antibody responses improved only in the people whose earlier vaccine doses had barely worked, and those people were unevenly split between the groups. That makes it a lead for future trials rather than a result.^[16]

Across all of this, the most encouraging human signal came from people eating ordinary food, and the largest capsule trial found no benefit at its dose.^{[4, 8]} In our reading, that makes food the natural foundation, with a capsule as an optional extra for people who want a measured dose.

Wheat germ is the richest common food source of spermidine, at roughly 24 to 35 mg per 100 g.^[9] Soybeans come next at up to about 21 mg.^[9] Mushrooms, peas, broccoli, cauliflower, spinach, green beans, hazelnuts and pistachios also contain notable amounts, while fruit has little.^[9] Estimates for a normal mixed diet run from about 5 to 15 mg a day, with European adults near the top of that range.^[9] So people were eating spermidine long before anyone put it in a capsule.

The values swing with variety, growing conditions, processing and storage,^[9] so read the table as a ranking with ballpark figures rather than lab readings.

Source: review of polyamines in food,^[9] converted from nmol/g and rounded.

Wheat germ is also the easiest way to add a real amount. One tablespoon (about 7 g) gives roughly 2 mg of spermidine.^[9]; you would need more than half a kilo of apples for the same amount. That tablespoon holds about twice the daily dose in the SmartAge capsules^[8] It also sits in the middle of what supplements deliver per daily dose, about 0.5 to 6 mg.^{[19, 24]} A tablespoon a day uses up about 200 g a month, and plain wheat germ is one of the cheaper foods on the cereal shelf. It stirs easily into yogurt, muesli or a smoothie.

Wheat germ is still wheat, so it does not suit people with celiac disease, gluten sensitivity or a wheat allergy. For them, soy, mushrooms, peas and beans are wheat-free sources,^[9] and the same caution applies to wheat germ supplements, as the safety section explains.

Whatever you eat, food is not your only supply, because your gut bacteria make spermidine too.^[3] The body's own production tends to fall with age, so food matters more in older people.^[9] That makes supplement doses hard to judge, because a capsule lands on top of a personal baseline that can differ a lot from one person to the next.

If you want a measured, standardized dose, the EU route is clear: the only authorized spermidine supplement ingredient is spermidine-rich wheat germ extract from common wheat (Triticum aestivum).^[12] It is capped at the equivalent of 6 mg of spermidine a day for adults.^[12] Pure synthetic spermidine is not an authorized food ingredient, and no health claim for spermidine has been approved.^{[11, 12, 19]}

What EU law allows

Under Regulation (EU) 2015/2283, a food ingredient that nobody ate in significant amounts before 1997 counts as a novel food and needs approval before sale.^[13] Spermidine-rich wheat germ extract took a shortcut. In December 2017 its maker filed a so-called substantial-equivalence notification under the old novel-food law.^[13] That route involved no full safety review by EFSA, the EU food-safety agency.^[13] Even so, the extract now sits on the EU's Union list of novel foods, which also sets its conditions of use.^[12]

Under those conditions, a food supplement for adults may supply the equivalent of 6 mg of spermidine a day, and pregnant and breastfeeding women are excluded.^[12] In Germany and Austria, products have to match the listed specifications.^[12] The EU changed those in March 2020 to allow more cadaverine, an amine that occurs naturally in wheat germ.^[13] Spermidine capsules are sold as food supplements, not medicines, so they need no prescription.^{[12, 19]} Switzerland has its own food law and its own novel-food approvals. We have not verified the extract's Swiss status, so check the product's label and the Swiss distributor.

What the label can and cannot tell you

The listing covers the ingredient rather than one brand, so a compliant product may use the original Graz extract or another extract that meets the same specifications.^[12] Plain ground wheat germ is a different case: it is an ordinary food, and the novel-food authorization concerns the concentrated extract.^{[12, 19]} Some of these powders are still sold at high prices as spermidine products while delivering only about 0.5 mg a day.^[19] Other products do not state their spermidine content at all.^[19]

Two other labels deserve a closer look. A label reading 'spermidine trihydrochloride' means a purified salt of spermidine, not a wheat germ extract, and that salt is not an authorized EU food ingredient.^[12] One industry-funded trial tested it at 40 mg a day.^[15] Buckwheat sprout flour grown with added synthetic spermidine has no EU approval either, according to Germany's consumer advice centers (April 2026).^[19]

No label may promise a health benefit either. One application sought permission to claim that spermidine keeps hair in its growth phase.^[11] EFSA ruled in 2011 that this was really about treating a hair-loss condition.^[11] Food health claims cannot cover treating a condition, so the claim was not authorized.^[11] Marketing that hints spermidine prevents disease, extends life or regrows hair is running ahead of what regulators have signed off. A sober label is therefore a good first filter when you compare products.

Which doses trials have tested

Sorted by daily dose, the trials show a pattern: those that looked for a benefit used low doses, while high doses were tested mostly for absorption and safety.

Sources: the trial publications cited in each row; POLYCAD status from its registry record, as of October 2026^[23]

In trials of spermidine on its own, doses above 6 mg have so far been tested only for absorption and safety. Those absorption results do not suggest that more is simply better. In a German study, even 15 mg a day for five days left blood spermidine unchanged, while spermine, which the body builds from it, went up.^[14] POLYCAD is the first such trial to look at benefit, and its results are not yet published.^{[17, 23]}

The products on the shelf sit well below those trial doses, from about 0.5 mg a day to 5–6 mg in high-dose capsules.^{[19, 24]} Stay at or below the 6 mg cap from all supplements together, which means not stacking several spermidine products.^{[12, 24]} The higher doses in the table were tested only under study conditions. Even at the cap, a capsule adds less than a typical European diet already supplies.^[9]

What it costs

As of October 2026, spermidineLIFE, the brand of the Graz company behind the extract, sells its monthly pack of 60 capsules from €62.10 in its own shop.^[25] Other EU-compliant products can cost less, and plain wheat germ costs a small fraction of that per milligram of spermidine. The capsule gives you a measured, standardized dose, while wheat germ gives a similar amount plus fiber and B vitamins. So the choice is between convenience and price rather than right and wrong.

Some shopping questions have no answer in the research. No study has compared brands, and no trial has compared taking spermidine in the morning with taking it in the evening. A higher-dose import outside the EU rules is not safer, only less regulated. If you have a chronic condition or take medication, take these questions to your Hausarzt, Wahlarzt or Privatarzt before you buy.

Spermidine looks safe at the doses tested so far, with few side effects in trials, but the record is short.^[8] Small amounts are part of every normal diet.^[9] Capsule trials gave about 1 mg a day for up to 12 months,^{[6, 8]} and a nursing-home trial gave up to 3.3 mg a day in wheat germ rolls.^[7] Higher doses ran for shorter times: 6 mg a day for 13 weeks.^[16] and 40 mg a day of purified spermidine for 28 days^[15]

The safety checks behind that verdict found no clinically meaningful red flags. A safety study of the wheat germ extract found none in mice over 28 days or in 30 older adults over three months.^[6] The 12-month SmartAge trial also reported no serious side effects tied to the supplement.^[8] The EU approval adds guard rails of its own: it caps the dose for adults at 6 mg a day and leaves certain groups out.^[12] That cap counts all supplements together, so taking two spermidine products at once can push you past it.^{[12, 24]}

Who should not take it without medical advice

• If you are pregnant or breastfeeding, stick to food sources. The EU approval excludes these groups, not because harm turned up but because safety has not been established for them.^[12]
• Children are not covered either, since the approval is for adults only.^[12] Spermidine from food is fine for them, but concentrated capsules are not the right call.
• Wheat germ supplements carry wheat. The EU-authorized ingredient is a wheat germ extract, and spermidineLIFE states that its products contain gluten.^{[12, 24]} With celiac disease or gluten sensitivity, do not take a wheat germ supplement unless your doctor agrees. With a wheat allergy the same applies, because 'gluten-free' does not mean wheat-free, and the safety trial excluded people allergic to wheat germ or gluten.^[6] Soy, mushrooms, peas and beans are wheat-free food sources.^[9]
• If you take immunosuppressants, Germany's consumer advice centers advise using spermidine only after talking to a doctor.^[19] No major direct drug interactions are on record at the studied supplement doses, but that is not the same as saying none exist. If you take cancer drugs or strong autophagy modulators (rapamycin, high-dose metformin, hydroxychloroquine), talk to your Hausarzt or Wahlarzt first.

Spermidine and cancer

Cancer is the most delicate question in the field. Germany's consumer advice centers warn that high-dose spermidine can promote the growth of certain tumors.^[19] They advise people with cancer or on immunosuppressants to use it only after talking to a doctor.^[19] The animal data lean the other way. In mice, lifelong spermidine in the diet did not make tumors more common,^[2] and in one mouse study it reduced chemically induced liver cancer.^[22]

Mice are not patients, though, and human data in people with cancer are very thin. One small randomized trial gave spermidine to head-and-neck cancer patients during radiotherapy and reported less dry mouth and no serious side effects after three months.^[21] It was not built, though, to tell whether spermidine affects tumors.^[21] If you have active or recently treated cancer, do not start a spermidine supplement without your oncologist's input.

What is still unknown

The biggest open safety question is time. No human trial has run longer than 12 months, so none shows what taking spermidine for decades would do.^[8] If you want more spermidine in the meantime, a daily spoon of wheat germ is in our view the easiest first step. If you prefer a capsule for its measured dose, it is a reasonable experiment for a healthy adult without a wheat problem: pick an EU-compliant wheat germ extract that states its mg per dose, stay within the EU cap from all products together, and give it a fixed trial period in which you watch how you tolerate it, while the trials settle what it does in people. Soy and beans are the wheat-free route for people who avoid wheat.^[9] For any health decision based on this guide, talk to your Hausarzt (Germany), your Wahlarzt or Privatarzt (Austria) or your Hausarzt or a specialist (Switzerland).