Spermidine and hair: does it actually work?

So does it actually grow hair, or is this just another wellness trend?

The short answer: yes, there’s an effect, but it’s modest, and so far it rests on a single decent clinical trial of 100 people. Spermidine extends the hair’s growth phase (the anagen phase). It doesn’t block DHT. It won’t bring back a bald scalp. And it will never replace a hair transplant in Turkey once baldness has set in.

It’s a food supplement for hair that genuinely helps in some cases. Support, not treatment. Here’s why, with the figures from the two studies that matter, the best food sources, and when it’s worth a try (or not).

What exactly is spermidine?

A small molecule your body already makes

Spermidine belongs to the polyamines, small organic molecules that your cells produce continuously from an amino acid (arginine). Nothing exotic.

It was first identified in semen back in the 17th century, which is where the name comes from. But it’s found pretty much everywhere: in the human body, in plants, and especially in certain fermented foods.

Autophagy, or the cell’s spring clean

Its main job in the body is to switch on autophagy.

Picture a cell doing a spring clean. It sorts through what still works, throws out what’s broken, and recycles damaged proteins. That’s autophagy. Spermidine flips the switch.

In technical terms, it activates a cellular protein that kicks off the whole internal recycling programme. In plain English, it’s a signal to the cell: “clean the house before it falls apart“.

Why the hair follicle needs it

The hair follicle is one of the fastest-dividing structures in the human body. It works non-stop, churning out keratin (the protein that makes up hair), without ever pausing. Its cellular recycling has to run like clockwork.

When that internal cleaning slips, the hair cycle shortens. The growth phase becomes too brief. The hair falls out before it has reached full length.

That’s the door spermidine works through. Not a hormonal block, but a metabolic nudge.

The real question is what that looks like in actual people.

The human studies on spermidine and hair

The reference trial on 100 participants

The benchmark trial was published in 2017. Researchers recruited 100 people (men and women, average age 36) and followed them through 90 days of supplementation.

It was randomised, placebo-controlled and double-blind, so neither the participants nor the doctors knew who was getting what. The team pulled 100 hairs before and after the intervention, and measured how many were in the active growth phase.

The results:

• Spermidine group: +52% follicles in the active growth phase (from 24.6 to 37.4 on average)
• Placebo group: -20% follicles in the active growth phase
• Cell division marker (Ki-67): +12.7 points, statistically very significant
• Pull test at the end of the study: 0 positives in the spermidine group versus 68% in the placebo group

The pull test is when the dermatologist tugs gently on a strand of hair. If more than 10% of the hairs come away, the test is positive and points to active loss. Zero positives out of 50 people on spermidine. That’s a solid result.

What happens at follicle level

To see why it works, you have to look at what plays out under the microscope, on follicles grown in the lab.

One in vitro study cultured human follicles in a Petri dish with spermidine added at a very low concentration (0.5 micromoles). After 6 days:

• +20% extra hair growth compared with control follicles
• 47 to 52% of the spermidine follicles had moved into the transition phase, against 67% in the control group

In short, spermidine delays the move into the resting phase. The hair stays longer in “I’m growing” mode.

A quick reminder on the anagen phase (when the hair is actively lengthening): it normally lasts between 2 and 6 years. The longer it runs, the longer and thicker the hair gets. When it shortens, you slip into telogen effluvium, or you start to feel that your hair is thinning.

One trial only: keep that in mind

A 52% jump sounds huge. Stay measured.

The 2017 trial is still the only randomised controlled clinical study ever published on oral spermidine and hair. Just one. There’s been no independent replication since, and the exact composition of the supplement tested has never been made public.

Promising. Not yet confirmed at scale.

Where to find spermidine (and at what dose)

The foods richest in spermidine

Before you head to the chemist, take a walk through the kitchen. The Western diet provides on average 10 mg of spermidine a day. A handful of foods are particularly rich in it:

• Wheat germ: 24 to 35 mg per 100 g (top of the list)
• Mature cheeses (aged cheddar, brie): up to 20 mg per 100 g
• Soya and its products: around 18 mg per 100 g
• Mushrooms (shiitake, oyster): up to 16 mg per 100 g
• Seeds and nuts: 5 to 6 mg per 100 g

A tablespoon of wheat germ on a yoghurt already gives you 3 to 4 mg. Enough to keep a useful daily intake going, even if it won’t reverse an established loss on its own. Pair it where you can with a good intake of biotin, vitamin B9 and vitamin D, through a diet adapted to hair health. And keep an eye on your intake if you follow a strict vegan diet, where spermidine sources can vary widely.

Supplements: dose and duration

Longevity trials have used doses ranging from 0.9 to 15 mg a day. The 2017 hair trial never published the exact dose used.

In practice, most products on the market offer 1 to 6 mg a day of concentrated wheat germ extract.

You need at least 3 months before you can hope to see anything. Below that, there’s no judging.

One real catch on absorption. A 2023 study showed that even 15 mg a day of oral spermidine doesn’t significantly raise blood levels in the short term. In other words, the effect isn’t simply proportional to the dose. Taking more doesn’t mean getting more.

A health benefit beyond hair

A useful side note. In a study tracking 829 people over 15 years, those with the highest spermidine intake had a lower mortality rate. Other research backs up the link with cellular longevity. So this isn’t a gadget product. It’s a molecule that’s been seriously studied for its broader effects on ageing.

What it can actually change for your hair, specifically, is the next question.

Spermidine and baldness: what it can do (and what it won’t)

What it does

Spermidine acts on the length of the growth phase. It buys you more time during which the hair is actively growing. On a weakened cycle, the difference can become visible after a few months.

When is it worth considering a spermidine supplement?

• Seasonal diffuse shedding (more marked loss in autumn or spring)
• After telogen effluvium following stress, dieting or pregnancy
• On thinning hair without clearly bald patches
• As support after a transplant, to help the quality of the regrowth
• For people on a restrictive diet or who fast often, who may be running short

What it won’t do

Promising, yes. Magical, no.

Spermidine does not block DHT. For that, you need finasteride, the only molecule that acts on the hormonal cause of hereditary baldness. If your hair loss depends on the action of DHT on your follicles, spermidine on its own won’t be enough.

It also doesn’t stimulate circulation the way minoxidil does. And it can’t bring a dead follicle back.

The cases where it will clearly fall short:

• Established baldness (Norwood stage 3 and above, meaning as soon as the temples or the crown become clearly visible)
• Deeply receded temples, an extended crown
• Scarring alopecia (hair loss linked to follicle destruction with scarring, most often autoimmune in origin)
• Extensive alopecia areata (patchy hair loss linked to an autoimmune disease)

A supplement that can stop genetic baldness on its own simply doesn’t exist. Not spermidine, not MSM, and not any other hair growth product on the market today delivers on that promise.

What to do when hair loss is already established

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Spermidine supports. It doesn’t repair. Once the loss is marked, you need tools that act directly on the follicle, or that replace the follicles already gone.

When it comes to hair loss treatments, there are two main families.

Reference medical treatments

• Minoxidil, which extends the growth phase through a different mechanism from spermidine, with 40 years of clinical track record
• Finasteride, which blocks DHT at the hormonal root of the problem
• Hair mesotherapy, which injects vitamins and growth factors directly into the scalp
• Hair PRF, sustained-release growth factors, included in transplant packages with Dr Cinik
• Hair exosomes, which deliver a high concentration of growth factors, with results you can judge at around 3 to 6 months
• Hair PRP, included in every transplant package

Hair transplant, when the follicle is gone

Once a follicle is dead, no supplement will bring it back. A transplant is the only technique that durably repopulates a bald area. With Dr Cinik, two methods are favoured:

• The Sapphire FUE: follicle-by-follicle extraction, fine sapphire-blade incisions, quick healing
• The DHI: direct implantation with the Choi pen, for maximum density and precision on the hairline

The before / after results speak for themselves. A spermidine supplement can support regrowth after the procedure, helping the quality of the new cycle. It won’t replace it.

More than 20 years of experience, over 50,000 patients operated on, protocols compliant with ISHRS standards (the leading international scientific society in hair transplantation). The consultation is free and personalised. If you’re wondering whether a supplement, a medical treatment or a transplant is the right route for you, do ask for a first opinion.

Scientific references

Kiechl, S., Pechlaner, R., Willeit, P., Notdurfter, M., Paulweber, B., Willeit, K., Werner, P., Ruckenstuhl, C., Iglseder, B., Weger, S., Mairhofer, B., Gartner, M., Kedenko, L., Chmelikova, M., Stekovic, S., Stuppner, H., Oberhollenzer, F., Kroemer, G., Mayr, M., Eisenberg, T., Tilg, H., Madeo, F., & Willeit, J. (2018). Higher spermidine intake is linked to lower mortality: a prospective population-based study. American Journal of Clinical Nutrition, 108(2), 371-380. https://pmc.ncbi.nlm.nih.gov/articles/PMC6128428/

Madeo, F., Eisenberg, T., Pietrocola, F., & Kroemer, G. (2018). Spermidine in health and disease. Science, 359(6374), eaan2788. https://pmc.ncbi.nlm.nih.gov/articles/PMC6287690/

Muñoz-Esparza, N. C., Latorre-Moratalla, M. L., Comas-Basté, O., Toro-Funes, N., Veciana-Nogués, M. T., & Vidal-Carou, M. C. (2019). Polyamines in food. Frontiers in Nutrition, 6, 108. https://pmc.ncbi.nlm.nih.gov/articles/PMC6718104/

Ni, Y., & Hagiwara, A. (2021). New insights into the roles and mechanisms of spermidine in aging and age-related diseases. Aging and Disease, 12(8), 1948-1963. https://pmc.ncbi.nlm.nih.gov/articles/PMC8612618/

Ramot, Y., Tiede, S., Bíró, T., Abu Bakar, M. H., Sugawara, K., Philpott, M. P., Harrison, W., Pietilä, M., & Paus, R. (2011). Spermidine promotes human hair growth and is a novel modulator of human epithelial stem cell functions. PLOS ONE, 6(7), e22564. https://pmc.ncbi.nlm.nih.gov/articles/PMC3144892/

Rinaldi, F., Marzani, B., Pinto, D., & Ramot, Y. (2017). A spermidine-based nutritional supplement prolongs the anagen phase of hair follicles in humans: a randomized, placebo-controlled, double-blind study. Dermatology Practical & Conceptual, 7(4), 17-21. https://pmc.ncbi.nlm.nih.gov/articles/PMC5718121/

Schwarz, C., Horn, N., Benson, G., Wrachtrup Calzado, I., Wurdack, K., Pechlaner, R., Grittner, U., Wirth, M., & Flöel, A. (2018). Safety and tolerability of spermidine supplementation in mice and older adults with subjective cognitive decline. Aging, 10(1), 19-33. https://pmc.ncbi.nlm.nih.gov/articles/PMC5807086/

Senekowitsch, S., Wietkamp, E., Grimm, M., Schmelter, F., Merges, G., Kiehntopf, M., Sommer, C., Schick, P., & Weitschies, W. (2023). 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, 15(8), 1852. https://pmc.ncbi.nlm.nih.gov/articles/PMC10143675/