Roughly 55,000 adult consumers in the United States take popular chewy melatonin gummies to promote better sleep. But they may be getting a little more of the hormone than the label indicates. A study published April 25 as a letter in the Journal of the American Medical Association (JAMA) found that 88 percent of tested supplements were mislabeled.
The study follows a Centers for Disease Control and Prevention (CDC) report from last year about an alarming surge of excessive pediatric infestations of melatonin over the past 10 years.
[Related: Yes, you can overdose on melatonin. Here’s how to use the sleep supplements safely.]
Melatonin is a hormone naturally produced deep within the brain in the pineal gland. It is released into the bloodstream to regulate the body’s natural sleep cycles. Melatonin is considered a drug in some countries in the European Union, Japan, Canada, and the United Kingdom, making it only available through a prescription. The US Food and Drug Administration considers melatonin a dietary supplement, but manufacturers are not required to receive FDA approval or provide safety data on melatonin products.
For this study, a team of researchers from Cambridge Health Alliance in Massachusetts and the University of Mississippi tested 25 different supplements. According to the authors, the team selected the first 25 gummy melatonin products that displayed on the National Institutes of Health database for this study. The team dissolved the gummies and then measured the quantity of melatonin, cannabidiol (CBD), and other components in the supplements.
Most of the products tested had 20, 30, or 50 percent more melatonin than the quantity listed on the label. Four has less amounts of the hormone than promised, including one without any detectable levels of melatonin.
Twenty-two were “inaccurately labeled,” meaning they contained 10 percent more or less than the amount of melatonin on the label.
Five products listed CBD as an ingredient, but they all had slightly higher levels of CBD than indicated on the label. According to the FDA, “it is currently illegal to market CBD by adding it to a food or labeling it as a dietary supplement.”
[Related: The science behind our circadian rhythms, and why time changes mess them up.]
“One product contained 347 percent more melatonin than what was actually listed on the label of the gummies,” study co-author and professor of medicine at the Cambridge Health Alliance Pieter Cohen told CNN.
In response to the JAMA letter, Steve Mister, the president and chief executive of the Council for Responsible Nutrition, told The Washington Post that supplement companies are required to have “at least 100 percent of labeled dosage” in their products. “It’s not uncommon for companies to put in a little extra,” he added. “So, for instance, a melatonin product that’s labeled as 3 milligrams might put in 4 milligrams.”
Melatonin was the most cited substance in calls about children to US poison control centers in 2020. Drowsiness, headaches, agitation, and increased bed-wetting or urination in the evening hours are all potential side effects of melatonin use in children.
“It’s important, especially in kids, not to use melatonin until you’ve spoken with your pediatrician or your sleep doctor,” M. Adeel Rishi, a pulmonology, sleep medicine, and critical care specialist in Indiana and vice chair of the American Academy of Sleep Medicine Public Safety Committee, told PopSci last July. “The dose recommended in children is significantly lower than what is recommended in adults, and if you take too much of anything you have an overdose. Although it’s come to attention really in the last couple of years, we know that cases of melatonin among children have been on an upswing even before the pandemic.”
Other pediatric sleep experts stress the importance of good sleep hygiene and habits before starting melatonin. The new study’s letter also included a warning to parents that giving the gummies to children could result “in ingestion of unpredictable quantities” of melatonin.