We know you’re sick and tired of counting sheep.

There are few pleasures in life greater than a deep, restful sleep. Seriously, if we could go back in time and tell our 7-year-old selves not to complain about nap time, we would. But there are lots of things that can throw you off your nighttime game.

If you have regular trouble catching Zzz’s, you’ve probably looked into taking melatonin supplements. After all, there are countless bottles stocking drugstore shelves. How much do you really know about them, though?

What Is Melatonin?

For starters, melatonin is a hormone released by the brain that helps regulate the body’s circadian rhythm (a.k.a. your internal clock), explains David Lee, M.D., assistant clinical professor of medicine at the UCSF Fresno Medical Education Program. “It’s secreted by the pineal gland, which is at the base of the brain and regulated by light,” he says. “It’s a natural hormone that makes us sleep, and the moment the light goes away, like in the evening, that’s when our peak melatonin [is produced].”

Are Melatonin Pills Really Safe?

Since they aren’t regulated by the U.S. Food and Drug Administration, it might be hard to tell if there are preservatives and additives in the pills you’re taking, says Sanjeev Kothare, M.D., professor in the department of neurology and director of the pediatric sleep program at NYU Langone Medical Center. “Some [users] have experienced a little bit of allergic reactions, not from the melatonin, but from the preservatives or additives,” he says. (Lee emphasizes that it’s important to always buy the supplement from a reputable company, avoiding herbal remedy peddlers.)

Kothare says animal studies have linked melatonin to depression, reproductive issues, and immunological problems. While these results haven’t been replicated in humans, there also haven’t been any good studies showing the long-term safety of melatonin pills, says Kothare.

Still, Lee adds that no serious side effects have been reported. Though he does note that if you take too much of the supplement you may feel drowsy, get a headache, or experience some short-term memory loss. “Those are the common but pretty mild side effects,” he says. The important thing, Lee points out, is to take the correct amount.

“The biggest myth out there, especially for insomnia, is that more is better,” says Lee. In fact, when it comes to melatonin, less is actually more because your body already makes it. He suggests taking 0.5 milligrams if you do decide to try it. If that dosage amount is difficult to track down, buy one milligram pills and cut them in half.

The bottom line: Unfortunately, there’s not enough solid research out there to back up whether melatonin supplements are truly an effective and safe way to get your sleep on. If you’re still struggling to reach dreamland, Kothare does have several other suggestions: Try to maintain a similar sleep schedule during the week and on weekends, limit the use of electronics that emit blue light for one to two hours before bed time, and purchase a bright light source for use in the mornings to help regulate your body’s internal clock. Your dream journal will be filled in no time.

This story originally appeared on Women’s Health.

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