November 20, 2023
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In the U.S., melatonin is sold as an over-the-counter sleep aid. More parents are giving melatonin to young children, but researchers say its long-term risks are still unknown.
About one in five school-aged children now take melatonin as a regular sleep aid, including many kids who are in preschool, according to new research on the over-the-counter dietary supplement. But some sleep experts warn that reliance on melatonin may put young people at risk.
Melatonin is a naturally occurring hormone produced in the pineal gland. It helps regulate the body's circadian rhythm and acts as a signal to prepare the body for sleep. It also helps establish normal cycles of falling asleep and waking up.
Synthetic versions of the hormone have long been recommended as sleep aids for adults who struggle to fall asleep. While many countries classify melatonin as a drug that requires a prescription, it's available over the counter as a supplement in the U.S. and can be purchased in varying strengths. It increasingly has been sold in the form of child-friendly gummies, which signals to parents that melatonin is safe for kids.
Researchers at the University of Colorado Boulder sought to gain a better understanding of how parents are using melatonin to help their kids get regular sleep. Their research, published this month in JAMA Pediatrics, says the growing use of melatonin is concerning because there is limited safety and efficacy data surrounding its use in children and preteens.
“We hope this paper raises awareness for parents and clinicians, and sounds the alarm for the scientific community,” said Lauren Hartstein, the study's lead author and a postdoctoral fellow at the university's Sleep and Development Lab. “We are not saying that melatonin is necessarily harmful to children. But much more research needs to be done before we can state with confidence that it is safe for kids to be taking long-term.”
Surveys the researchers conducted showed a steep rise in melatonin use among kids over the last several years. As recently as 2018, only about 1.3% of parents in the U.S. reported that their children took melatonin.
During the first half of 2023, Hartstein and her colleagues surveyed about 1,000 parents with children of various ages. Among kids ages 5-9, 18.5% had been given melatonin by their parents in the previous 30 days. For preteens between 10-13, 19.4% had taken melatonin in the last 30 days. And among preschoolers between 1-4 years old, 6% had been given melatonin.
The grade-school and preteen children used melatonin for median lengths of 18 and 21 months, respectively. Preschoolers who took melatonin used it for a median length of a year, according to the survey.
The researchers also found that dosages tended to increase as children got older. Preschoolers took anywhere from 0.25 milligrams to 2 milligrams, while preteens got doses as high as 10 milligrams.
In adults, melatonin is sometimes recommended specifically for groups like late-shift workers, people recovering from jet lag and those who have mild insomnia. One large U.S. study found that melatonin use remains relatively low, but it has been increasing and more people are taking doses higher than the recommended amount of 5 milligrams per day. In 1999-2000, only about 0.4% of adults said they took melatonin. That rose to about 2.1% of adults by 2017-18.
The study notes that its survey data on children comes from parents in Colorado and isn't necessarily representative of the whole U.S. Still, researchers think the increase in melatonin usage is telling and that parents should consider being more judicious with it.
The researchers said they're concerned about melatonin's lax regulation in the U.S. They tested numerous melatonin products to see whether the amounts listed on their labels were accurate. In one instance, they found that the pills had more than three times as much melatonin than the label indicated. One product didn't contain any melatonin at all, while some supplements were found to contain other substances like serotonin, which is a precursor to melatonin.
Although some health care providers recommend melatonin as a short-term sleep aid for some groups of children — particularly those with autism or severe sleep problems — long-term use of the supplement is not well understood in young people. Limited studies have produced inconsistent results, according to the researchers.
"It is almost never a first-line treatment,” said Julie Boergers, a coauthor of the study and a pediatric sleep specialist at Rhode Island Hospital and the Warren Alpert Medical School of Brown University. “Although it’s typically well-tolerated, whenever we’re using any kind of medication or supplement in a young, developing body, we want to exercise caution.”
The study notes that the sale of melatonin in gummy form appears to contribute to an increased risk of unsafe consumption. Between 2012-2022, the authors found that reports of melatonin ingestion to poison control centers increased by 530%, mostly among children under 5. More than 94% of these cases were deemed unintentional, and about 85% were without symptoms.
If parents do choose to give their kids melatonin, doses between 0.5-1 milligram taken 30-90 minutes before bedtime should be effective, according to the American Academy of Pediatrics. Most children do not need more than 3-6 milligrams of the supplement.
The Mayo Clinic notes that melatonin can produce side effects like headache, dizziness, nausea and daytime drowsiness.
Boergers said the preferred method of dealing with sleep disturbances should be behavioral changes, such as limiting screen time at night, especially two to three hours before bed, and reinforcing regular sleep schedules. The blue light that comes from electronics and some energy-efficient lighting is known to reduce the natural secretion of melatonin, according to researchers from Harvard University.
The new study's researchers worry that giving children melatonin regularly could send them the message that sleep problems can be treated with pills instead of trying to modify behavior first.
“If this many kids are taking melatonin, that suggests there are a lot of underlying sleep issues out there that need to be addressed,” Hartstein said. “Addressing the symptom doesn’t necessarily address the cause.”
