Spermidine: Benefits, Foods, Side Effects and Dose

Spermidine is a natural compound found in every living cell and in foods such as wheat germ, soybeans and mushrooms. It has become one of the most talked-about longevity ingredients because it switches on autophagy, the process cells use to clear out and recycle worn-out parts. This guide explains what spermidine is, what studies show, the best spermidine foods, how much has been studied, side effects, and gluten-free options.

It is educational, not medical advice.

Key Takeaways

• Spermidine is a polyamine your body makes and gets from food. Levels inside cells decline with age.
• It triggers autophagy, the cell’s recycling process, and extended lifespan in yeast, worms, flies and mice.
• In people, a 20-year study linked higher dietary spermidine with lower mortality.
• Wheat germ and soybeans are the richest food sources. Many supplements are made from wheat germ, so gluten-free sources matter if you avoid gluten.
• Trials used about 1 mg a day for up to a year, and it was well tolerated.

What Is Spermidine?

Spermidine belongs to a family of compounds called polyamines, along with putrescine and spermine. Cells need polyamines to grow and renew. Your body makes spermidine, and food adds more. Its concentration inside cells declines as we age (Eisenberg et al., 2009), which is one reason researchers began testing whether adding it back could support healthy aging (Madeo et al., 2018).

Our guide to autophagy explains what this cell recycling process is and what research shows about when it starts.

How Spermidine Works: Autophagy

Autophagy means “self-eating”: cells break down damaged proteins and worn-out parts and reuse the materials. It tends to slow with age. Spermidine is one of the best-studied natural triggers of autophagy.

Spermidine fits into a wider longevity toolkit alongside polyphenols such as pterostilbene; our anti-aging research overview explains how these approaches fit together.

• Lifespan in model organisms. Adding spermidine extended the lifespan of yeast, flies and worms, and of human immune cells grown in the lab, and it reduced oxidative stress in aging mice (Eisenberg et al., 2009).
• Fasting. Spermidine levels rose during fasting or calorie restriction in yeast, flies, mice and human volunteers. When researchers blocked the body’s own spermidine production, fasting triggered less autophagy in yeast, worms and human cells (Hofer et al., 2024). More in fasting and longevity.

Autophagy has a targeted form for mitochondria, called mitophagy, which urolithin A is studied to support. Our guide to mitophagy explains the difference.

Spermidine Benefits: What Studies Show

Diet and longevity

In a study that followed 829 adults aged 45 to 84 for 20 years, people in the top third of dietary spermidine intake had a death rate of 15.1 per 1,000 person-years, compared with 40.5 in the bottom third. The difference in risk between the top and bottom thirds was similar to being 5.7 years younger, and the link held after adjusting for lifestyle and other diet factors (Kiechl et al., 2018). This kind of study shows a link, not cause and effect.

Heart and lifespan in animals

In mice, oral spermidine extended lifespan, and in old mice it preserved heart function and increased autophagy and mitochondrial activity in heart cells (Eisenberg et al., 2016).

Memory in older adults

• Pilot trial. In 30 older adults who felt their memory was slipping, 3 months of a spermidine-rich wheat germ extract moderately improved performance on a memory task compared with placebo (Wirth et al., 2018).
• Larger 12-month trial. In 100 adults aged 60 to 90 with the same concern, 0.9 mg of spermidine a day from wheat germ extract did not change the main memory measure or other outcomes compared with placebo. Exploratory analyses pointed to possible benefits for verbal memory and inflammation, which the researchers plan to test at higher doses (Schwarz et al., 2022).

For other brain-focused options, see creatine for brain health and the best anti-aging supplements backed by human research. For what a human study measured on hair and the doses used, see our guide to spermidine for hair growth.

Spermidine Foods

A review of polyamines in food found cereals, legumes and soy foods have the most spermidine, with wheat germ and soybeans highest (about 2,437 and 1,425 nmol per gram). Fruit has the least (Muñoz-Esparza et al., 2019).

Richest sources	Good sources	Lowest
Wheat germ, soybeans	Mushrooms, peas, green beans, hazelnuts, pistachios, spinach, broccoli, cauliflower	Most fruit, such as apples, pears and oranges

There is no official recommended daily intake for spermidine or other polyamines (Muñoz-Esparza et al., 2019).

Mushrooms also supply ergothioneine, another compound studied for healthy aging. See ergothioneine benefits: what it is, food sources, dosage and safety. Urolithin A is another food-linked compound studied for healthy aging; see urolithin A foods.

Gluten-Free Spermidine

Most spermidine supplements, including those used in the human trials above, are made from wheat germ extract (Schwarz et al., 2022). Wheat germ contains gluten, so if you avoid gluten, look for spermidine from a gluten-free source and check the label for a gluten-free statement. Soybeans are another rich natural source.

Coming soon from Synchronicity: our Urolithin A + Spermidine Capsules are planned with spermidine from a gluten-free source, not wheat germ, plus urolithin A 500 mg per 2 capsules. Join the waitlist on the product page to hear when they launch; no payment is taken.

How Much Spermidine Has Been Studied?

Study	Spermidine a day	How long	What it found
Safety trial, 30 older adults	1.2 mg	3 months	Well tolerated
Memory trial, 100 older adults	0.9 mg	12 months	No change in main memory measure
Absorption study, 12 healthy adults	15 mg	5 days	Blood spermine rose; spermidine did not

In the absorption study, 15 mg a day raised blood levels of spermine, which the body makes from spermidine, but not spermidine itself, suggesting it is converted before it reaches the bloodstream (Senekowitsch et al., 2023). Follow the directions on your product label.

Spermidine Side Effects and Safety

In a 3-month trial in older adults, 1.2 mg a day caused no differences from placebo in vital signs, weight, blood tests or self-reported health, and more than 85 percent of doses were taken as planned (Schwarz et al., 2018). In the 12-month trial, side effects were similar in the spermidine and placebo groups (Schwarz et al., 2022).

• Gluten: wheat germ products contain gluten; choose a gluten-free source if you avoid it.
• Cell growth: polyamines help cells grow, so anyone being treated for cancer should talk with their oncologist before taking spermidine.
• Pregnancy and breastfeeding: there is little safety data, so ask your clinician first.
• Medicines: check with your clinician if you take prescription medicine.
• Under 18: talk with a clinician first.

Spermidine Side Effects: What People Ask

The short answer is reassuring: spermidine is a natural part of everyday food, and in the longest trial so far side effects were no more common than with placebo. In that study, 100 adults with an average age of 69 took 0.9 mg of spermidine a day or a placebo for 12 months; 89 percent completed it, and adverse events were balanced between the groups (Schwarz et al., 2022).

• Is it safe long term? Twelve months is the longest human trial so far, with side effects similar to placebo.
• Is it already in my diet? Yes. Wheat germ, soybeans, mushrooms, peas and nuts all supply it; see spermidine foods.
• Who should ask first? Anyone being treated for cancer, because polyamines help cells grow, and anyone pregnant, breastfeeding or taking prescription medicine.

How to take spermidine comfortably

• Check the source: many products are made from wheat germ, so choose a gluten-free source if you avoid gluten.
• Make it a daily habit: the trials gave it every day for months, so steady use matches what was studied.
• Follow your label: amounts differ between products.

Spermidine is often paired with urolithin A, which supports mitophagy; see urolithin A benefits and mitophagy. Our Urolithin A + Spermidine Capsules are planned with urolithin A 500 mg and spermidine 6 mg from a gluten-free source per 2 capsules. They are coming soon; join the waitlist on the product page to hear when they launch, and no payment is taken.

Spermidine vs Urolithin A and NAD+

Spermidine, urolithin A and NAD+ are often grouped as longevity ingredients, but they work on different parts of cell renewal:

• Spermidine supports autophagy, the general recycling of worn-out cell parts.
• Urolithin A supports mitophagy, the recycling of worn-out mitochondria specifically. See urolithin A benefits and how it compares with NAD+.
• NAD+ is a coenzyme cells use to turn food into energy and to fuel repair enzymes. Levels fall with age; see what NAD+ is and why it declines, our NAD+ ingredient page and our cellular energy and mitochondria guide.

Our NAD+ Nasal Spray and Enhanced NMN support cellular energy and healthy aging. For a wider view, see supplements for longevity. For how urolithin A and NMN differ and whether to take them together, see urolithin A vs NMN. Spermidine and NMN work on different pathways, and our guide to spermidine and NMN covers how they differ and taking them together.

Sources

• Eisenberg T et al. Induction of autophagy by spermidine promotes longevity. Nature Cell Biology, 2009. DOI
• Madeo F et al. Spermidine in health and disease. Science, 2018. DOI
• Hofer SJ et al. Spermidine is essential for fasting-mediated autophagy and longevity. Nature Cell Biology, 2024. DOI
• Kiechl S et al. Higher spermidine intake is linked to lower mortality: a prospective population-based study. The American Journal of Clinical Nutrition, 2018. DOI
• Eisenberg T et al. Cardioprotection and lifespan extension by the natural polyamine spermidine. Nature Medicine, 2016. DOI
• Wirth M et al. The effect of spermidine on memory performance in older adults at risk for dementia: A randomized controlled trial. Cortex, 2018. DOI
• Schwarz C et al. Effects of Spermidine Supplementation on Cognition and Biomarkers in Older Adults With Subjective Cognitive Decline: A Randomized Clinical Trial. JAMA Network Open, 2022. DOI
• Muñoz-Esparza NC et al. Polyamines in Food. Frontiers in Nutrition, 2019. DOI
• Senekowitsch S et al. High-Dose Spermidine Supplementation Does Not Increase Spermidine Levels in Blood Plasma and Saliva of Healthy Adults: A Randomized Placebo-Controlled Pharmacokinetic and Metabolomic Study. Nutrients, 2023. DOI
• Schwarz C et al. Safety and tolerability of spermidine supplementation in mice and older adults with subjective cognitive decline. Aging, 2018. DOI

Frequently Asked Questions

What is spermidine good for?

Spermidine triggers autophagy, the cell’s recycling process. It extended lifespan in animal studies, and higher dietary intake was linked with lower mortality in a 20-year study of adults. Human supplement trials have focused on memory in older adults.

Which foods are highest in spermidine?

Wheat germ and soybeans are the richest sources, followed by mushrooms, peas, green beans, nuts such as hazelnuts and pistachios, spinach, broccoli and cauliflower. Fruit has the least.

How much spermidine should I take a day?

There is no official recommended intake. Longer human trials used about 1 mg a day (0.9 to 1.2 mg) from wheat germ extract. Follow your product label.

Does spermidine have side effects?

In trials lasting 3 to 12 months, side effects were similar to placebo. Choose a gluten-free source if you avoid gluten, and check with your clinician if you are pregnant, take medicine or are being treated for cancer.

Is spermidine gluten free?

Spermidine itself is, but many supplements are made from wheat germ, which contains gluten. Look for a gluten-free source and label statement.

How long does spermidine take to work?

Human trials measured changes after 3 to 12 months of daily use.

Can you take spermidine with urolithin A or NAD+?

They support different parts of cell renewal (autophagy, mitophagy and energy metabolism) and are often taken together. Check with your clinician if you take prescription medicine.

Is spermidine safe to take long term?

The longest human trial lasted 12 months, with 0.9 mg a day, and adverse events were balanced between the spermidine and placebo groups.

Who should not take spermidine?

Check with your clinician first if you are being treated for cancer, are pregnant or breastfeeding, or take prescription medicine. Choose a gluten-free source if you avoid gluten.

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.