A lot of young kids are taking melatonin to help get a full night’s sleep, according to a new study published in the journal JAMA Pediatrics.

Researchers surveyed about 1,000 families and found that roughly 20% of children ages 5 to 13 had taken melatonin in the past month.

They’d been using melatonin for more than a year on average, according to the study.

“I’m not surprised that parents are giving children melatonin, but I am surprised about the length of time that this study showed parents giving the children melatonin,” said Dr. Gabrina Dixon, a pediatrician with Children’s National Hospital in D.C.

Dixon said she recommends using melatonin as an aid, but only for short-term use.

“Parents should not be giving melatonin long-term without guidance from a health care provider,” Dixon said.

There is limited research into melatonin, and it is not clear whether children may have any negative side effects as a result of using it over a long period of time.

“I’d definitively say more research needs to be done on that,” Dixon said.

Dixon urged parents to get to the bottom of why their kids are not sleeping properly, rather than trying to fix it through melatonin alone.

“I always say, ‘why aren’t the kids sleeping?’ Dixon explained. “Is it a sleep behavior or is something else going on?”

Melatonin is a hormone the brain produces in response to darkness. It helps with the timing of circadian rhythms and with sleep.

“Research suggests that melatonin plays other important roles in the body beyond sleep, however, these effects are not fully understood,” according to the National Center for Complementary and Integrative Health.

Melatonin dietary supplements can be made from animals or microorganisms, but usually they’re made synthetically.

The supplements can help with certain conditions, such as jet lag, certain sleep disorders and anxiety before and after surgery.