Tired? Can’t fall asleep at night? Instead of taking a sleeping pill, millions of people reach for the dietary supplement melatonin. But it’s not without risks.

Melatonin is a sleep hormone that is naturally produced by the body and is also available as a popular supplement. Studies show that it can be helpful, but only for some people in certain situations.

“If you’re jet-lagged or they’re trying to sleep after working a night shift. Or for people 70 or older, the supplement might help because their body might not produce enough melatonin on its own,” explained Lauren Friedman, Consumer Reports health editor.

Still, there are lots of other people using melatonin. Is it safe?

“You should never take a dose of more than 10 mg. And you should actually consider starting, if you want to try melatonin, at only about 0.2 to 0.5 mg.,” said Friedman.

Taking more than what your body produces could cause you to be sleepy and mentally or physically slow the next day.

Because melatonin isn’t regulated like prescription and over-the-counter drugs, look for labels from ConsumerLab.com, NSF International, USP, or UL. They provide some peace of mind that a product contains what’s on the label.

Also, check with your doctor before starting melatonin. It can interact with blood pressure and diabetes drugs. And be aware of possible side effects. After taking melatonin, some people report dizziness or nausea, or say they’re drowsy the next day. So it’s best not to drive when using it.

Consumer Reports also says there’s not enough research to know whether melatonin is safe to use for longer than three months.