Why You Should Think Twice Before Taking Melatonin For Sleep.

Melatonin has become a popular sleep aid for people who have trouble catching their zzz’s but don’t feel comfortable taking medication. But, even though it’s sold in the seemingly-innocuous vitamin section, experts say you should think twice before reaching for the supplement—especially if you plan to use it regularly.

Melatonin is a hormone produced by your brain’s pineal gland. Your body starts producing it naturally when the sun goes down (i.e. when the lights go dim), making you feel sleepy. As a result, it helps you fall asleep at night. It also helps you stay asleep, since your body continues to produce melatonin to some degree until it gets light outside. Melatonin supplements work similarly to the natural hormone, except they aren’t triggered by light—they just go to work once you take them.

Research has found that the right dosage for melatonin as a sleep aid is 0.3 milligrams, but many melatonin supplements are marketed in 3 milligram tablets. That’s 10 times the amount your body needs, and that’s assuming you’re only taking one pill or capsule. What’s more, because melatonin pills are classified as a dietary supplement, they’re pretty unregulated by the FDA. As a result, the supplement may say they contain a certain amount of melatonin, while the pills actually have a different amount.

That’s concerning, Indira Gurubhagavatula, M.D., MPH, an associate professor of sleep medicine at the University of Pennsylvania’s Perelman School of Medicine, tells SELF. “What is the quantity of the drug that you’re actually getting and how much is in each of those pills?” she says. “Since it isn’t regulated, it could be any amount. People have tested the tablets and found that the amounts are all over the place.” (It’s also possible for the supplement’s ingredients list to say one thing, while the actual pills contain something else entirely or additional ingredients you may not be aware of, Gurubhagavatula says.)

Taking too much melatonin isn’t known to have an immediate negative impact on your health, Mehran Movassaghi M.D., director of California’s Providence Saint John’s Men’s Health Center, tells SELF, but it can leave you feeling groggy and headachy. And, in addition to the hangover-like effects, taking too much melatonin is simply a waste of money.

There’s also a concern of throwing off your body’s circadian rhythm, i.e. your body’s physical, mental, and behavioral changes that follow a 24-hour cycle, when you take melatonin supplements, says sleep medicine doctor and neurologist W. Christopher Winter, M.D., of Charlottesville Neurology and Sleep Medicine. “Messing around with your circadian rhythm is probably not a great thing,” he tells SELF. Do it too often, and you may put yourself at risk for shift work sleep disorder, he says, a condition in which people experience insomnia and excessive sleepiness when they should be awake. (The World Health Organization has classified the disorder—a circadian rhythm sleep disorder often caused by unusual shift-based work schedules—as a probable carcinogen, meaning it may contribute to the development of cancer.)

“To me, the biggest danger is you’re toying with this very fundamental part of your brain that’s keeping everything on schedule,” Winter says. “It’s not something I’d want to mess with.”

You also have to be careful with timing, Gurubhagavatula says. Take a melatonin supplement too early, and you could fall asleep at the wheel. Take it too late, and you may not feel sleepy until well past the time you want to get to bed.

If you take melatonin here and there for jet lag, it’s not really a big deal, says Movassaghi, who does it himself on occasion. However, if you’re constantly relying on it to get to sleep, it could cause your body to produce less melatonin naturally, creating a vicious cycle in which you need more melatonin supplements to get to sleep. “Eventually it can offset your own melatonin creation for a few days,” he says. The result: You’d need a few nights of broken sleep to get back to normal.

Having trouble falling asleep? Gurubhagavatula recommends taking a look at what you’re doing, both throughout the day and right before bed. She says having caffeine, smoking, alcohol, and lack of physical activity during the day can throw your ability to fall asleep out of wack. But she also says it’s crucial to shut down all electronics at least a half hour before bed, since they give off light that fights your body’s natural melatonin production.

And, if you’re in bed and can’t sleep, she suggests getting up and doing something relaxing that doesn’t involve bright light. Then, head back to bed when you feel tired.

Still can’t sleep? It’s time to talk to your doctor or a sleep specialist. Gurubhagavatula says they may be able to help pinpoint a reason that melatonin supplements wouldn’t help with anyway.