We often think of hormones as having a negative effect on skin. And some can. But there’s at least one hormone that can help protect the skin from the sun and reverse signs of aging.

However, most people don’t realize this hormone can affect their skin. They just think of it as a sleep aid. But it can have a dramatic impact. Let me show you how.

You may have guessed that I’m talking about melatonin. A lot of people don’t even realize that melatonin is a hormone. But it is! The brain makes it in the pineal gland. And it secretes it according to light patterns and our circadian rhythms. Its interaction with circadian rhythms are what allow it to help us sleep better. Sometimes the brain needs help figuring out that it’s time to sleep. Melatonin can help give it the signal it needs to wind down.

Inside the body, melatonin has a number of other important functions beyond contributing to sleep. It helps your immune system function properly. It helps to regulate body weight and reproduction. It has anti-cancer effects, fighting tumors and reducing the side effects of chemo. And thanks to how it affects your sleep-wake cycles, it can even help you fight jet lag.

More Than a Sleep Hormone

But it turns out that the brain isn’t the only place our bodies make melatonin. Our skin cells can actually make it too. And they can definitely put it to work. Melatonin may soothe the brain, but it’s also a powerful antioxidant. So its presence in the skin cells makes it uniquely suited to help fight damage from UV radiation. (Of course, if it makes you fall asleep sitting out in the sun, that’s another story!)

You certainly know that not getting enough sleep can make you look and feel older than you are. But melatonin’s anti-aging effects extend beyond helping you get your beauty rest. Its antioxidant effects are definitely a big part of that. Oxidative stress can break down collagen and cause inflammation.

Because of its chemical structure, melatonin can neutralize a variety of free radical forms. And in response to UV radiation, melatonin produces more antioxidants. The metabolites of other antioxidants can often produce more oxidative stress. Melatonin does the opposite. Plus, melatonin makes other antioxidative enzymes work more effectively, particularly in response to stress.

These effects combine to make melatonin particularly suited to protecting the skin from UV damage. Studies have found that administering melatonin prior to UV exposure offers protection to the skin. In one study, researchers exposed fibroblasts (cells that make collagen) to UV radiation. Melatonin increased cell viability and decreased apoptosis (cell death). In fact, the survival rate went from 56% to 92.5% when the researchers exposed the cells to melatonin prior to UV radiation.

Melatonin also protects collagen by keeping genes from carrying out photodamage in response to UV rays. And it supports mitochondria, the “engines” of the cells, so the cells can keep functioning properly—especially those that make collagen.

Topical Melatonin Protects the Skin

One study of humans enlisted 20 healthy participants. They received either topical melatonin or a placebo either before or after UV exposure. The researchers assessed sunburn on the participants’ skin after exposure. Interestingly, only those who received the melatonin prior to exposure experienced any benefit. Obviously, the placebo offered no protection. But applying melatonin after the exposure was too late.

This is likely because UV rays create free radicals immediately, which start causing stress and wreaking havoc right away. In particular, they can break down collagen, leading to wrinkles and sagging. And your immune system has to mount an inflammatory response as soon as it detects the threat.

If you wait until a couple hours have passed to apply melatonin, the damage has already occurred. But if you have melatonin in place, its free radical scavengers can get to work immediately to stop oxidative stress in its tracks. In fact, it works even better than vitamin C or a form of vitamin E to neutralize free radicals.

Some dermatologists that recommend melatonin encourage patients to use it at night. If you do that, it syncs right up with your skin’s natural repair rhythms. But topical application won’t make you sleepy. So if you’d rather use it during the day, that’s ok too.

I have had many patients experience a negative reaction to melatonin applied to their face. So I recommend it internally or topically on the forearm, but not the face.

One Possible Downside

Another possible downside of topical melatonin is that it can activate the melanocytes in your skin. Melanocytes are responsible for creating pigment. So melatonin can end up darkening your skin.

Melatonin applied to the scalp can increase hair growth. This could be a good solution for those whose hair is starting to thin. And no, it won’t make your hair darker. (You’ll have to stick to dye if you were hoping to cover some grays!)

Keep an eye out for more information about melatonin in the future, too. Researchers are just starting to investigate its potential for regenerating cells and tissues. This could mean good things for your collagen and even whole organs like the liver. It’s definitely an exciting area of study.

Of course, if you haven’t been sleeping well, you can start with using melatonin supplements to help you get some rest. Some doctors recommend taking 3 mg half an hour before you’d like to be in bed. It can help you get your beauty rest. That might be all your skin needs to look radiant!