Melatonin doesn’t cause hair loss. However, topical melatonin may actually stop or reverse hair loss. Side effects reported with topical melatonin include temporary redness or other color changes, sensitivity, or itching.

Melatonin is a hormone that’s naturally made by your brain. It’s important for your circadian rhythm or internal clock. As it gets darker in the evening, your brain makes more melatonin in order to promote sleep.

Melatonin can also have other effects in the body. For example, it has antioxidant and anti-inflammatory properties and can impact mood.

Melatonin may affect hair health in people with androgenetic alopecia (AGA), which causes male- and female-pattern baldness. Researchers estimate that AGA impacts over 50% of older men and 15% of women after menopause.

Melatonin doesn’t contribute to hair loss caused by AGA. Instead, it may help to stop hair loss or even promote hair growth. Keep reading to discover more.

There’s no evidence that melatonin causes hair loss. In fact, there’s evidence of the opposite. Melatonin may help to stop hair loss or boost hair growth.

What causes androgenetic alopecia?

Androgens, specifically dihydrotestosterone (DHT), are hormones that contribute to AGA. These chemical messengers have various roles in the body, including being involved in the cycle of hair growth.

Too much DHT can impact the hair follicle, shortening the hair growth phase and leading to hairs that are thinner and shorter. Over time, this can lead to increased hair loss and hair thinning.

Genetics also plays a role in AGA. That means that having a close relative — such as a parent or sibling — with AGA increases your risk of getting it as well.

There’s some evidence that topical melatonin, applied directly to the skin or scalp, may help stop or even reverse hair loss.

A 2023 study reviewed the results of 11 studies of topical melatonin in people with hair loss. It reported that in most of the studies, topical melatonin:

  • improved hair growth on the scalp
  • boosted the density of hair on the scalp
  • increased the thickness of hairs

A 2024 review notes that studies have found that melatonin has anti-androgen effects and is also involved in regulating hair growth. Researchers summarized several clinical studies where melatonin was found to have a beneficial effect on hair loss.

How does melatonin help with hair growth?

While research is ongoing, several studies have started to pick apart the mechanism by which melatonin may help with hair growth.

A 2022 study used cells in a lab to model the human hair follicle. It found that the dermal papillae, which are cells involved in sending signals for hair growth, had higher levels of melatonin receptors.

This means that melatonin binding to melatonin receptors in this area may promote hair growth. The researchers found that adding melatonin to their model boosted the expression of genes associated with hair growth.

A 2024 study in mice supported this, finding melatonin sped up the hair cycle. Melatonin boosted signaling related to hair growth in dermal papillae, and led to signaling in stem cells in the hair follicle that promoted hair growth.

More research is needed on people.

Using melatonin topically doesn’t appear to be associated with significant side effects. An older review points out that participants in some studies of topical melatonin for hair loss have reported mild, but temporary, side effects like:

You may be aware that oral melatonin supplements are often used to promote sleepiness. Because of this, it’s not a stretch to wonder if topical melatonin may also cause you to feel sleepy.

A small 2016 study investigated this. Researchers asked 10 healthy participants to apply a high dosage (12.5%) of melatonin cream to 80% of their skin. However, no significant cognitive effects, such as sleepiness, were seen.

You may consider topical melatonin for hair loss if other treatments haven’t worked or have caused you significant side effects, or if you’re looking for a complementary and alternative medicine (CAM) approach to hair loss.

Common FDA-approved medications for hair loss in people with AGA include topical minoxidil (Rogaine) for men and females with AGA and oral finasteride (Propecia) for males with AGA.

Other medications, such as oral spirolactone (for females) and oral dutasteride (Flomax) may be prescribed off-label for hair loss.

Certain procedures may also be used for hair loss, including:

A variety of topical melatonin products are available. These typically come in the form of a serum that you apply to your scalp.

There’s no set treatment regimen for topical melatonin. A 2023 study notes that, after analyzing prior research, an effective dosage is 0.0033% to 0.1% topical melatonin applied once daily for between 90 to 180 days.

It’s important to know that the FDA doesn’t regulate melatonin like a drug. So, it’s important to purchase topical melatonin from a reputable source.

When in doubt, it’s always good to speak with a doctor before trying out topical melatonin for hair loss. They can give you specific recommendations on how exactly to use it.

Melatonin doesn’t lead to hair loss. However, topical melatonin may be beneficial for preventing further hair loss or boosting hair growth. More research is needed on people.

There are limited mild side effects associated with topical melatonin.