Should You Be Using Melatonin For Hair Growth? Experts Weigh In 

Melatonin impacts so much more than a good snooze. Case in point: Your melatonin levels can influence just how glowing and smooth your skin is: "Melatonin is critically important for your skin and plays a significant role in skin repair from environmental exposure, UV light, stressors, pollution, and so on," says board-certified dermatologist Keira Barr, M.D., on an episode of Clean Beauty School. Beauty sleep is very much real.

Given these beauty-related benefits, it's only natural to wonder whether topical melatonin can procure similar results. It turns out, melatonin-infused skin care products do carry some scientific weight—and because scalp care is skin care, melatonin may have some hair growth benefits, too.

Before diving into the benefits, you should know that the exact science behind melatonin and hair growth isn't fully understood. "Melatonin is critical for a healthy follicle," says Alan Meyers, senior vice president and chief scientific officer at MONAT, but researchers are still trying to determine why topical melatonin can promote hair growth1; that being said, there have been some studies with noteworthy results.

"A number of clinical studies have been done showing some improvement in androgenic alopecia2 in men and women after applying topical melatonin at night," explains board-certified dermatologist Cynthia Bailey, M.D., founder of DrBaileySkinCare.com. (Androgenic alopecia, if you're unfamiliar, is commonly referred to as male- or female-pattern baldness.) "It works particularly well in women, perhaps due to melatonin's ability to modify the hair follicle response to estrogen3."  

A recent 2022 in vitro study also found that melatonin can signal human dermal papilla cells4 (aka, cells found at the bottom of hair follicles that play a role in hair growth), which may be able to explain its positive effects.

Finally, "Melatonin reduces free radical stress3 at the follicle level that can lead to reduced hair growth," Bailey adds. After all, oxidative stress plays a major role in hair loss5, as the accumulation of free radicals over time can cause the follicle to close off, which limits growth and can eventually lead to shedding. That's why experts tell you to tend to your scalp with antioxidants to fend off those free radicals—and melatonin does function as a powerful antioxidant.

You might be wondering: Can taking melatonin supplements provide similar hair growth benefits? Well, not exactly. "Melatonin is readily absorbed through skin, raising melatonin skin levels. Oral melatonin is not readily bioavailable because the liver rapidly removes it from the bloodstream, as it enters from the gut in something called 'first pass metabolism,'" says Bailey. "This means that oral melatonin supplements do not significantly increase skin melatonin levels because the liver rapidly removes melatonin before it can reach the skin." Translation? Topical melatonin is the way to go.

Since the mechanisms behind melatonin and hair growth aren't fully understood, there aren't too many melatonin hair serums on the market right now—a few brands, however, do leverage melatonin's benefits along with other scalp-supporting ingredients like caffeine and vitamin C (we listed them below!). 

Although melatonin does function as an antioxidant, let's not forget that melatonin is a hormone—and a vital hormone at that. "As with all hormones, such as estrogen, testosterone, and cortisone, studies looking at the resulting blood levels with any treatment are important," notes Bailey. "Thus far, topical scalp application for the treatment of hair loss has not been shown to exceed normal blood levels of melatonin3." So no, topical melatonin in skin care formulations shouldn't make you feel sleepy or groggy—according to another 2016 study, a topical melatonin cream of 12.5% was not associated with any sort of cognitive dysfunction6.