What do you do when you can't get your kids to settle down to go to sleep? For a growing number of parents, the answer is melatonin.

Recent research shows nearly one in five school-age children and adolescents are now using the supplement on a regular basis. Pediatricians say that's cause for alarm.

"It is terrifying to me that this amount of an unregulated product is being utilized," says Dr. Cora Collette Breuner, a professor of pediatrics at the University of Washington.

Melatonin is a hormone produced by your brain that helps regulate sleep-wake cycles. It's also sold as a dietary supplement and is widely used as a sleep aid.

Lauren Hartstein, a postdoctoral researcher who studies sleep in early childhood at the University of Colorado, Boulder, says she first got an inkling of melatonin's growing use in children and adolescents while screening families to participate in research.

"All of a sudden last year, we noticed that there was a big uptick in the number of parents who were regularly giving [their kids] melatonin," Hartstein says.

Hartstein and her colleagues wanted to learn more about just how widely melatonin is being used in kids. So they surveyed the parents of nearly 1,000 children between the ages of 1 to 14 across the country. She was surprised by just how many kids are taking the supplement.

"Nearly 6% of preschoolers, [ages] 1 to 4, had taken it, and that number jumped significantly higher to 18% and 19% for school-age children and pre-teens," she says.

As Hartstein and her co-authors recently reported in the journal JAMA Pediatrics, most of the kids that were using melatonin had been on it for a year or longer. And 1 in 4 kids were taking it every single night.

Breuner says that kind of widespread use is deeply troubling for several reasons. She says because melatonin is easy to find on store shelves, people assume it's just as safe as taking a vitamin. But melatonin is a hormone, and she says there's no real data on long-term use in children. She notes there are concerns that it could potentially interfere with puberty and glucose metabolism, among other things, though research is lacking.

"I counsel patients and families about this on a daily basis — and my colleagues — that when we don't know something in terms of what the long-term effect is, especially on a growing brain, a growing body, then we shouldn't use it without more data," Breuner says.

Melatonin supplements aren't regulated with the same rigor as prescriptions and over-the-counter medications. Research has found some can contain much more melatonin than what's listed on the label — in some cases, potentially dangerous amounts. One recent study found some gummies — which Hartstein and her colleagues found to be the most common form of melatonin given to kids – contained CBD.

"The studies are really concerning in the fact that you don't know what you're getting," says Dr. Nia Heard-Garris, a researcher at Northwestern University and a pediatrician at Lurie Children's Hospital of Chicago.

Heard-Garris says she understands why desperate parents turn to melatonin to help their kids sleep. "I'm also a mom, so for all the parents out there with kids that have sleep issues, I get it. I've been there. I am there. And I have also used melatonin, when my son was much younger," she says.

But Breuner and Heard-Garris both say that, given all the unknowns, the focus needs to be on sleep hygiene first. That means doing things such as turning off screens at least an hour before bedtime, using blackout shades and noise canceling machines or earplugs, and not letting kids stay up more than an hour or two past their normal bedtime on weekends and vacations.

"Now, if we're in a situation that we have tried everything, they've seen a sleep specialist, you know, we've kind of done all of the things, then I will prescribe melatonin," Heard-Garris says.

Dr. Heard-Garris says parents should definitely talk to their pediatrician before giving kids melatonin because it's possible to give too much. Signs of an overdose in kids include irritability, severe headaches, stomach pains and dizziness, and severe drowsiness, including difficulty rousing a child. "Those are the red flags," she says. Side effects can also include increased bed-wetting, "because the sleep is so deep," she adds.

Breuner notes that the only research "with some rigor" on melatonin use in children involves those with autism spectrum disorder, and in those cases, parents should also consult their doctor before giving their children the supplement.

Pediatric overdoses of melatonin have skyrocketed in recent years, jumping more than 500% between 2012 and 2021. While most kids were treated at home, hospitalizations also went up, and two children died during that time period, according to research published by the Centers for Disease Control and Prevention.

If parents do decide to give their children melatonin after checking with their pediatrician, Breuner recommends looking for a supplement with a USP label, which means its contents have been third-party tested by the U.S. Pharmacopeia to ensure they are free of contaminants and contain the amount of melatonin listed on the label.

The American Academy of Pediatrics recommends that melatonin only be used as a short-term way to help kids get rest.

This story was edited by Jane Greenhalgh