Spermidine and longevity

Spermidine is a small molecule called a polyamine. Your body makes it, your gut bacteria make some of it, and you also eat it. It was first isolated from human semen in 1678 by Antonie van Leeuwenhoek, which is where the name comes from. The biology, not the etymology, is what matters here.

The reason researchers care about spermidine for longevity is one main mechanism: autophagy. Autophagy is your cells' recycling system. It chews up damaged proteins and worn-out organelles and reuses the parts. As you age, autophagy slows down. Damaged proteins accumulate. Cells work less well. Most interventions that extend lifespan in animal studies, from caloric restriction to rapamycin to exercise, increase autophagy. Spermidine does the same thing.

In the landmark 2016 paper from Tobias Eisenberg, Frank Madeo and colleagues (Nature Medicine), spermidine added to drinking water extended median lifespan in mice and improved heart function in old animals. The effect depended on autophagy: when autophagy was blocked, the lifespan benefit disappeared. The same paper also reported a parallel observation in humans: in 829 participants of the Bruneck cohort, higher dietary spermidine intake tracked with lower blood pressure, lower incidence of cardiovascular disease (a composite that included vascular death) and around 40% lower risk of fatal heart failure. The all-cause mortality link was added two years later by Kiechl et al. 2018, with extended follow-up and validation in a second cohort.

A more recent mechanistic paper from the same Graz group (Hofer et al., Nature Cell Biology, 2024) showed that fasting itself raises cellular spermidine across species (yeast, flies, mice and human volunteers), and the in-vivo lifespan/healthspan benefits of fasting are abolished when the polyamine pathway is blocked. In other words, spermidine is now thought to be one of the molecules that mediates the benefits of caloric restriction.

Important: nearly all of this is animal and cell biology. The headline mouse results are robust. Whether they translate cleanly to humans is a separate question, and the human data is more mixed, as we will see below.

Spermidine is one of the few longevity compounds where the field's center of gravity is in the German-speaking world. Most of the foundational work comes from the Frank Madeo lab at the University of Graz in Austria, in collaboration with the Karl Franzens University and BioTechMed-Graz. The 2016 Nature Medicine paper, the 2018 Science review, the SmartAge clinical trial protocol with Charité Berlin, and the 2024 Nature Cell Biology fasting paper all run through this network.

This matters for two practical reasons. First, the Bruneck cohort that linked dietary spermidine to lower mortality is Italian-South-Tyrolean, in a German-speaking region in northern Italy. Second, the only spermidine supplement that holds EU Novel Food authorization as a wheat germ extract is made by Longevity Labs+, a spin-off based in Graz, Austria. The product is sold under the brand spermidineLIFE.

This does not mean the science is settled, or that the Austrian product is automatically the best buy. It just means that if you read a recent peer-reviewed spermidine paper, there is a roughly 60 percent chance Frank Madeo is in the author list. Knowing where the research comes from helps you read it more honestly. The Madeo group has been transparent about funding ties, but several of the human studies were partly supported by Longevity Labs. That is a normal academic-industry relationship, not a scandal, but it is the kind of context you should know.

The Vienna University of Applied Sciences (Pekar group, Wiener Neustadt) and the Charité Berlin / DZNE Berlin (Wirth, Schwarz, Flöel) are the other two DACH centers that have run human spermidine trials. Together with Graz they account for most of the clinical evidence base.

There are two strands of human evidence. They tell slightly different stories.

Observational cohorts

The Bruneck Study (Kiechl et al., American Journal of Clinical Nutrition, 2018) followed 829 adults aged 45 to 84 in northern Italy from 1995 to 2015 (20 years), with food frequency questionnaires used to estimate dietary spermidine. Higher intake (third tertile vs. lowest) was associated with about a 15 to 25 percent lower all-cause mortality, robust to adjustment for age, smoking, BMI, calorie intake, physical activity and other variables. The same paper validated the finding in a second Salzburg-area cohort.

This is real and impressive. It is also still observational. People who eat a lot of spermidine eat a lot of whole grains, legumes and fermented cheese, which means they eat a Mediterranean-style diet. Whether the spermidine itself did the work, or whether spermidine is a marker for the underlying diet pattern, the cohort cannot answer.

Randomized trials

The biggest randomized trial to date is SmartAge (Schwarz et al., JAMA Network Open, 2022). One hundred older adults with subjective cognitive decline were randomized to 12 months of spermidine-rich wheat germ extract (delivering about 0.9 mg spermidine per day) or placebo. The primary outcome was memory performance on a Mnemonic Similarity Task. The trial was negative. There was no measurable benefit on memory, on blood biomarkers, on brain MRI, or on most secondary outcomes.

A smaller earlier pilot (Wirth et al., Cortex, 2018) had been mildly positive in 30 participants over 3 months, with a medium effect size on mnemonic discrimination. The larger and longer SmartAge trial did not replicate this. That is how science is supposed to work: small positive pilot, larger trial, see whether it survives. Here, it did not.

A counter-signal

The Pekar group (Pekar et al., Wiener Klinische Wochenschrift, 2020) ran a 3-month double-blind multicenter pilot in 85 older adults aged 60 to 96 with mild to moderate dementia in six nursing homes in Styria, Austria. The higher-dose group (about 3.3 mg/day spermidine) had a small improvement on cognitive testing — notably a +2.23-point gain on the MMSE in the mild-dementia subgroup (p = 0.026), with most other endpoints non-significant — versus the lower-dose group. The trial had no placebo arm in the traditional sense (both arms got spermidine, just at different doses), the sample was small, and the population was different from SmartAge (established dementia vs. subjective decline). It does not undo SmartAge, but it is one of the reasons the field has not closed the book on cognitive benefit.

Honest reading. For cognition in healthy older adults at risk for dementia, the best-quality trial is negative. For cardiovascular mortality in observational cohorts, the signal is consistent. The mechanistic basis (autophagy) is plausible. None of this is a reason to take or avoid spermidine; it is the actual state of the evidence in 2026.

Long before anyone made a spermidine pill, people ate spermidine every day. The most comprehensive peer-reviewed food database is Muñoz-Esparza et al., Frontiers in Nutrition, 2019. The numbers below are converted from that paper (with a few values from the broader literature). They vary widely with variety, ripeness, processing and storage, so think of them as orders of magnitude.

Food	Approximate spermidine	Notes
Wheat germ (raw or toasted)	~25-35 mg/100 g	The single richest common food source
Soybeans (dried)	~15-20 mg/100 g	Plus tofu, natto, tempeh
Aged cheese (cheddar, parmesan, blue cheese)	~1-2 mg/100 g	Younger cheeses much lower
Mushrooms	~3-9 mg/100 g	Higher in shiitake and oyster mushrooms
Green peas	~5-7 mg/100 g	Fresh; canned slightly lower
Navy beans, white beans	~5-12 mg/100 g	Cooked from dry
Broccoli, cauliflower	~2-3 mg/100 g
Pears, apples	~0.5-1 mg/100 g
Whole grain bread	~0.5-1 mg/100 g

A reasonable mixed European diet provides somewhere between 5 and 15 mg of spermidine per day. The Bruneck cohort's highest tertile was around 12 mg/day. Mediterranean-style eating, with whole grains, legumes, vegetables and some aged cheese, gets you there without trying.

If you are looking for the highest-density real food, the answer is wheat germ. A tablespoon (about 7 g) of toasted wheat germ provides roughly 2 mg of spermidine, in the same range as a typical supplement capsule. It costs a few euros per kilogram at any DACH supermarket and works in yogurt, muesli, smoothies and bread.

Gut bacteria also make spermidine. A meaningful share of the spermidine in your body never came from food at all. This is one reason the dose-response curve from supplements alone is murky: you are adding to a background that varies a lot between people.

This section is deliberately vendor-neutral. You are an adult and you can shop. Our job is to explain the regulatory and evidence landscape.

EU Novel Food status. In the EU, a food ingredient that was not consumed to a significant degree before 1997 is treated as a Novel Food under Regulation (EU) 2015/2283 and needs explicit authorization. Spermidine-rich wheat germ extract from Triticum aestivum, as developed by Longevity Labs+ (Graz, Austria), is the one spermidine ingredient with EU authorization. The European Commission authorized it via Implementing Regulation (EU) 2017/2470 with the specifications amended by Commission Implementing Regulation (EU) 2020/443 (25 March 2020), following an EFSA Novel Food safety assessment. The authorization specifies maximum daily levels for adult food supplement use, and food-supplement labels in DE, AT and CH have to match those specs.

Practical implications. A spermidine supplement legally sold in Germany, Austria or Switzerland either: (a) uses the authorized Longevity Labs+ wheat germ extract, (b) uses a different wheat germ extract that is also compliant with the Novel Food authorization (this is allowed), or (c) is in a legal gray zone, sometimes sold cross-border or as a 'wheat germ' product that does not explicitly market the spermidine content. Pure synthetic spermidine is not authorized as a food supplement in the EU.

What concentrations are actually proven? The Wirth 2018 pilot used about 1.2 mg/day. The SmartAge trial used about 0.9 mg/day for 12 months. The Pekar 2020 nursing-home trial used about 1.9 to 3.3 mg/day for 3 months. The Bruneck cohort tertiles spanned roughly 6 to 12 mg/day, all from food. Most authorized supplements deliver something in the 1 to 3 mg/day range per serving, which sits inside the studied band but at the low end of the dietary cohort signal.

A note on price. A monthly supply of an EU-authorized spermidine-rich wheat germ extract supplement in DACH typically costs 30 to 70 euros, with some variation by country (CH usually most expensive, AT often cheapest given proximity to the manufacturer). A bag of wheat germ at the same supermarket costs roughly 3 to 5 euros and lasts a month at one tablespoon per day. The supplement gives you a measured, standardized dose. The wheat germ gives you the dose plus fiber, magnesium, vitamin E, B vitamins, and zinc. Neither approach is wrong. They are different products.

What we cannot tell you. Whether brand A is better than brand B. Whether a higher-dose unauthorized product from abroad is safer or more effective than the EU-authorized one (it is not generally safer, just less regulated). Whether timing matters. Whether spermidine works better with fasting (mechanistically plausible per Hofer 2024, not tested in a human trial). These are open questions. Use this guide to ask better ones at your Hausarzt, Wahlarzt or Privatarzt appointment, especially if you have a chronic condition or take medication.

Short answer. Dietary spermidine is part of every human's normal diet. At the doses delivered by EU-authorized supplements (about 1 to 6 mg/day), the safety record so far is reassuring but limited.

The Schwarz et al. 2018 paper in Aging combined animal and human safety data and reported no clinically meaningful adverse signals for spermidine-rich wheat germ extract over 3 months in older adults. The 12-month SmartAge trial (Schwarz 2022) also did not report serious adverse events linked to the intervention. The EU Novel Food authorization sets limits on maximum daily intake for adults and excludes certain populations from the authorized use.

Where caution is warranted

• Pregnancy and lactation. EU Novel Food authorization for spermidine-rich wheat germ extract excludes pregnant and breastfeeding women, not because harm has been shown but because safety has not been established for that population. If you are pregnant or breastfeeding, food sources only.
• Children. Same logic. The authorization does not cover children. Spermidine from food is fine; concentrated supplements are not appropriate.
• Active or recently treated cancer. This is the hardest question in the field. Spermidine drives autophagy, which can be either protective or growth-promoting depending on the tumor type and stage. The Schwarz 2018 paper notes that in mouse studies, lifelong dietary spermidine did not increase tumor frequency, and in some chemically induced liver cancer models it was protective. But the human evidence in active cancer patients is essentially zero, and Madeo's own group warns that polyamine-driven autophagy could in principle support certain established tumors. If you have active or recently treated cancer, do not start a spermidine supplement without your oncologist's input.
• Wheat germ origin. Spermidine supplements made from wheat germ contain gluten, even when very low. People with celiac disease or non-celiac gluten sensitivity should choose a certified gluten-free preparation or skip the supplement entirely.
• Drug interactions. No major known direct pharmacokinetic interactions are documented at studied food-supplement doses. That is not the same as 'no interactions exist'. If you take immunosuppressants, anticancer drugs or strong autophagy modulators (rapamycin, metformin at high dose, hydroxychloroquine), this is a conversation for your Hausarzt or Wahlarzt before adding spermidine.

What we still do not know

• Whether decades of supplementation are safe. The longest human trial is 12 months.
• Whether spermidine prevents dementia in people who do not yet have symptoms (SmartAge enrolled subjective cognitive decline, not unaffected adults).
• Whether the cardiovascular signal from cohorts translates into a randomized prevention effect.
• Whether spermidine combined with fasting, exercise or rapamycin produces additive benefit in humans.

For any health decision based on this guide, talk to your Hausarzt (Germany), Wahlarzt or Privatarzt (Austria) or Hausarzt / Spezialist (Switzerland). This guide is education, not a prescription.