Long before microscopes and molecular biology, longevity was already being studied with quiet devotion. In the 28th scroll of Ishinho, the "heart of medical prescription," there are instructions for creating and preserving jingqi, the life force, with a focus on sexual energy. The Imperial Family of Japan and its physicians preserved this treasure of oriental medicine for more than 1,000 years, and the underlying ideas are thought to be over 2,000 years old.
One of the longevity practices described in that scroll is male arousal without ejaculation. What did these early practitioners intuitively sense? It would take modern science several hundred years to offer a possible explanation, and the answer turns out to involve a molecule found in every cell of your body.
What is spermidine, and where did the name come from?
Spermidine is a naturally occurring polyamine first identified in human semen by microscopy pioneer Anton van Leeuwenhoek in 1678, who named the crystals spermine and spermidine. Today we know these polyamines are produced in every cell of the body, not only in sperm, and that spermidine plays a central role in cellular renewal.
Research associates spermidine with a range of effects on cellular health, most notably its role in supporting autophagy, the body's vital cell renewal and recycling process, which gradually slows with age [1]. The mechanism behind autophagy was mapped by Japanese scientist Yoshinori Ohsumi, whose work in this field was later recognized with a Nobel Prize.
Could seminal retention play a role?
This is where ancient practice and modern biology begin to resonate. Oxford Healthspan founder and CEO Leslie Kenny postulates that arousal without ejaculation may allow a practitioner to "resorb his own spermidine and thereby benefit from a boost in cellular autophagy and the resulting beneficial biological effects."
Whether or not a man chooses to preserve his life force in this way, spermidine remains a key component of ejaculate, and its role there is increasingly well understood. Polyamines, spermidine among them, appear to support sperm motility [2]. The seminal plasma of infertile men has also been found to contain much lower polyamine levels, which suggests a relationship between virility and the maintenance of spermidine [3].
Why spermidine matters for women, too
Spermidine is just as significant in female fertility and reproduction. Research indicates that polyamines contribute to the "activation of development of blastocysts, implantation, placentation, fetal growth, and development required for the successful establishment and maintenance of pregnancy in mammals" [4]. Their role does not end there.
For Radiant Rachel and the discerning women who make longevity a daily practice, this is the more compelling story: spermidine is not a niche curiosity tied to one sex. It is a molecule your body already knows, one that supports cellular vitality across the whole span of life.
Where else is spermidine found in the body?
Because spermidine is produced by every cell, it appears throughout the body and in the fluids that nourish new life. Two sources stand out for what they reveal about its role in health: breast milk and the gut microbiome. Both illustrate how deeply this polyamine is woven into human biology.
Spermidine and spermine in breast milk
Breast milk contains high levels of spermidine and spermine, and their presence appears to be meaningful. The neonatal small intestine is immature at birth and matures during breastfeeding and weaning, which makes the composition of breast milk especially important during this window.
Polyamines in breast milk, which are strongly influenced by the mother's nutrition, have been reported to both "decrease intestinal permeability of macromolecules and reduce the frequency of food allergies in children" [5]. It is one more example of spermidine quietly supporting renewal at the very start of life.
Spermidine and the gut microbiome
Spermidine is not only produced by your own cells. It is also generated by the gut microbiota, the community of bacteria, archaea, and viruses that evolved alongside us to support digestion, nutrient absorption, protection against pathogens, and the production of essential metabolites.
Your overall spermidine level is shaped by several inputs at once: how much your cells produce, how much your gut microbes produce, how much you take in through food and supplements, and how much you excrete. Understanding these inputs is the first step toward supporting your levels intentionally.
Why spermidine levels decline with age
Spermidine production is not fixed. As we age, the amount produced by our cells and gut microbes decreases, while the body's need for dietary sources rises. This gradual shift is one reason many people become more attentive to spermidine in their 40s, 50s, and beyond.
This is not a decline to fear or fight. It is simply a signal, an invitation to nourish your cellular renewal more deliberately through the foods you eat and, where helpful, the supplements you choose.
How to increase your spermidine levels
You can support your spermidine levels through two practical routes: a diet rich in naturally spermidine-dense foods, or a food-derived spermidine supplement when reaching those levels through diet alone is not realistic. Most people find a combination of both is the most sustainable approach.
Spermidine in food
Some of the richest dietary spermidine comes from Japanese cuisine. Natto, a fermented soybean dish, is especially concentrated: daily intake of 50 to 100g over a two-month period was shown to significantly raise volunteers' polyamine levels. Natto is time-consuming to make, hard to find in many regions, and has a smell, texture, and taste that can challenge even devoted longevity enthusiasts.
Other spermidine-rich foods include shiitake mushrooms, soy sauce, and soy miso, along with oranges, grapefruit, pumpkin, and aged cheese. Building these into your routine is a simple, whole-food way to nourish your levels.
Spermidine supplements
If eating 50 to 100g of natto daily is not realistic, a food-derived spermidine supplement can help you maintain your levels. When choosing one, source and formulation matter. Given Japan's scientific authority on autophagy and its culinary heritage of spermidine-rich foods, it is a natural place to look.
We believe Primeadine is a thoughtful choice. Because it is food-derived, Primeadine delivers not only spermidine but also the companion polyamines mentioned throughout this article, including spermine and putrescine. Putrescine is a precursor that helps the body produce more spermidine, while spermine supports DNA methylation.
Primeadine is carefully formulated in Japan using plant-derived ingredients, then tested once in Japan and again by a third party in the United States for purity and heavy metals. You can read more about our Quality and Testing protocols and, if you avoid gluten, compare Primeadine Original with Primeadine GF.
References
2. Pavine L. C. Lefèvre, Marie-France Palin, Bruce D. Murphy, Polyamines on the Reproductive Landscape, Endocrine Reviews, Volume 32, Issue 5, 1 October 2011, Pages 694–712, https://doi.org/10.1210/er.2011-0012
4. Zhang, Y., Bai, J., Cui, Z. et al. Polyamine metabolite spermidine rejuvenates oocyte quality by enhancing mitophagy during female reproductive aging. Nat Aging 3, 1372–1386 (2023). https://doi.org/10.1038/s43587-023-00498-8
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