If you’re one of the nearly three in four Americans who struggle to get a restful night’s sleep, chances are you’ve used, or at least heard of, melatonin.

A hormone naturally produced in our brains, melatonin is commonly known as “the sleep hormone.” It is also one of the most popular over-the-counter sleep remedies on the market: Melatonin supplement use among Americans has increased four-fold since 2000.  

So what’s the catch? While melatonin may improve sleep for some people, most sleep medicine specialists agree that melatonin isn’t a one-size-fits-all, risk-free cure for sleep problems. “Sleep and sleep disorders are very individual,” says Michael Breus, PhD, a clinical psychologist known as The Sleep Doctor and a Fellow of The American Academy of Sleep Medicine. “Melatonin isn’t a panacea, nor is it suitable for everyone.” 

Keep reading to learn who may benefit — and who should stay away from — the so-called “vampire hormone.” 

What Is Melatonin?  

Melatonin is hormone that’s naturally released by the pineal gland, a pea-sized gland in the brain. Melatonin helps to regulate your 24-hour sleep-wake cycle — aka your circadian rhythm. As you might guess by its nickname (“vampire hormone”), the release of melatonin is triggered by darkness — in other words, it only comes out at night. When receptors in your retinas detect a lack of light, a signal is sent to the suprachiasmatic nucleus (SCN) in the hypothalamus to activate the pineal gland. 

“Melatonin levels rise in the evening, prompting physiological changes like lowered body temperature and respiration rate, signaling the body to prepare for sleep,” Breus says. Once melatonin is released into the bloodstream, physiological changes occur such as decreased body temperature and respiration rate, along with drowsiness. Levels typically stay elevated throughout the night before returning to negligible daytime amounts.

Regulating your sleep-wake rhythm seems to be its main function, but research suggests that melatonin might have other potential benefits (including anti-aging and anti-cancer properties) as well that aren’t fully researched or understood.

LEARN MORE: How Blue Light Impacts Sleep

What Are Melatonin Supplements? 

Besides the all-natural version produced in your brain (also called endogenous melatonin), there are over-the-counter melatonin supplements available today (in certain countries — more on that below). You’ll typically find melatonin supplements in two main forms: natural and man-made. (Breus also notes there is a first-of-its-kind plant-based melatonin called Herbatonin.)

However, in this case, “natural” doesn’t necessarily mean safe. In fact, because natural melatonin supplements are created from animals, there’s a risk of contamination. That’s why it’s a safer bet to go for the synthetic form of the supplement. You should be able to find this labeled clearly on the supplement’s packaging, or ask your pharmacist or doctor if you’re not sure. 

Note: In most places in the European Union, New Zealand, Australia, and some other countries, you will need a prescription from your doctor to buy melatonin.  And in the U.S. and Canada, melatonin supplements are the only hormone that can be purchased without a prescription. Since it’s considered a dietary supplement, its safety and efficacy aren’t regulated by the Food and Drug Administration (FDA). (More on that below.) 

How Do Melatonin Supplements Work? 

Melatonin supplements work in a similar way as the natural hormone, helping the systems in your body align in the evening in preparation for rest, Breus says. As noted above, melatonin works by bringing about physiological changes – including lowered body temperature and respiration rate — that put your body in a quieter, drowsy state to promote sleep. When you take a supplement you’re adding to those physiological signals, Breus says. 

What many people get wrong is that melatonin doesn’t act like a prescription sleeping pill. It’s not a sedative, so it won’t quiet a busy mind or treat other issues that can cause insomnia. And unlike prescription sleep aids, you need to take it an hour or two before bed to see any effect. Many people take it right before bed or in the middle of the night, expecting it to knock them out, Breus notes — and it won’t.

What Foods Have Melatonin? 

While a few foods, such as tart cherries and walnuts, naturally contain melatonin and can modestly boost production of melatonin, melatonin levels are much more impacted by light.

There is another one ingredient in particular that can help improve melatonin levels: tryptophan, an essential dietary amino acid that’s a precursor to melatonin production. Tryptophan can be found in most protein-rich foods, especially lean protein, eggs, cheese, fish, seeds, nuts, and legumes.

Who Should Take Melatonin?

Person Standing with Suitcase in Airport“A melatonin supplement can be effective in the right situations,” says Breus. “It works best when your internal clock has been thrown out of whack, like from jet lag or shift work, or if you have a circadian rhythm disorder, such as delayed sleep phase syndrom.” (In any case, Breus advises talking with your physician before taking melatonin.) 

Here are a few research-backed use cases for melatonin:

Jet lag: Melatonin has been shown help reduce jet lag by syncing your internal clock with the time change. One analysis of 10 studies deemed melatonin to be “remarkably effective” at reducing the effects of jet lag, and found “occasional short-term use” to be safe. (Find more science-backed strategies to manage jet lag here.)

Improving sleep efficiency: If you’re having a few restless nights and are trying to get more rest, studies  have found that melatonin may increase sleep efficiency by around 2 percent. Translation: You’ll fall asleep about 4 minutes faster, and sleep around 13 minutes longer (though that’s not much to write home about). 

Delayed sleep phase syndrome: Adults and teens with this sleep disorder have trouble falling asleep before 2 a.m. and have trouble waking up in the morning. Research suggests that a combination of melatonin supplements, a behavioral approach to delay sleep and wake times until the desired sleep time is achieved, and reduced evening light may even out sleep cycles in people with this syndrome. 

How Much Melatonin Should I Take?

Though there are no standardized dosages for adults, Breus suggests starting with a low dose of .1 to 5 mg and seeing how your body responds. Though supplements are sold up to 10 mg, that’s much more than your body needs, plus those larger amounts haven’t been studied, he notes.

Potential Drawbacks of Melatonin 

Because the FDA doesn’t regulate melatonin — or any dietary supplement, for that matter — it isn’t  tested for safety, potency, or effectiveness and can contain harmful ingredients, or an inaccurate ingredient list.

One study found that in more than 71% of melatonin supplements, the amount of melatonin was more than 10% different from what the product label indicated. Some products contained as much as 478% more melatonin than advertised.

Breus suggests asking your doctor or pharmacist for a recommendation rather than just plucking a random brand off the drug store shelf.

And, because melatonin hasn’t been studied for long-term use it’s not meant to be a solution for chronic sleep problems. Some sleep specialists recommend trying it for a couple of weeks, maybe a month or two, and see if that gets you back to a regular sleep cycle. If not, it’s a good idea to talk to your doctor about what’s keeping you awake.

Bottom line? Before reaching for a sleep genie-in-a-bottle, there are multiple ways that you can naturally improve your sleep.

You can take up a new practice like meditation, adjust your meal times to your body’s natural rhythm, or optimize your restorative deep sleep with one of these tips.

Who Should Not Take Melatonin? 

According to physicians at the University of North Carolina School of Medicine, people who are taking prescription steroid drugs; antiseizure medications; have heart disease, stroke, or high blood pressure; severe mental illness; or an autoimmune disease or immune-system cancers such as leukemia and lymphoma should not take melatonin without the close supervision of a physician.  

To that list Breus adds those who are on diabetes medication and women who are trying to conceive as well as pregnant women and nursing mothers. “There’s not enough research to confirm that taking melatonin while pregnant or breastfeeding is safe,” he says. “Because melatonin levels naturally rise throughout pregnancy, one potential risk of supplementing is giving your body too much of the hormone.” Find more warnings and potential drug interactions with melatonin here.

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