According to a new study, certain melatonin supplements have significantly different dosages than advertised.

According to a recent study published April 24 in JAMA, people who take the over-the-counter supplement melatonin for improved sleep may be getting more—or less—of the medicine than they realise. Researchers from the Cambridge Health Alliance and the University of Mississippi discovered that 22 of the 25 gummy supplements claiming to contain melatonin contained significantly different levels than stated on the bottle.

Melatonin levels in the 22 mislabeled goods ranged from 74% to 247% of the amounts reported on their labels. One had no melatonin at all. Dr. Pieter Cohen, lead author and associate professor at Harvard Medical School and internist at Cambridge Health Alliance, says he wasn’t surprised. Despite the fact that melatonin supplements have long been “thought to be relatively safe,” the Food and Drug Administration (FDA) does not strictly regulate supplements as it does over-the-counter medications. “Supplement manufacturers don’t need to keep the FDA happy,” he claims. “They don’t need to prove anything to the agency—so they do whatever they want” when it comes to quantity. Not worrying over quality control keeps goods much cheaper to create.”

Cohen decided to investigate melatonin gummies after a 2022 report revealed that contacts to U.S. poison control centres for paediatric melatonin use increased by more than 500% between 2012 and 2021. “The majority of those calls were due to unintentional ingestions,” he adds, adding that gummies are particularly enticing to children, who may mistake the drug for candy. Though the majority of the children were unharmed, over 20% of poison-control calls described symptoms such as gastrointestinal upset, cardiovascular issues, and more. Melatonin has not been thoroughly examined in children, despite the fact that 10% of American parents have at least one child who takes it, according to Consumer Reports.

Previous research has also discovered that the amount of melatonin in supplements varies greatly. A 2017 Canadian study discovered that 71% of over-the-counter pills tested—some of which were presumably sold in the United States at the time—had melatonin levels that were mislabeled by at least 10%, the same criterion used in the new paper. The fact that these findings have been largely repeated more than five years later with a fresh generation of products demonstrates how the unregulated supplement market in the United States gives no meaningful incentive for producers to change, according to Cohen.

Because melatonin is a hormone produced in the brain and released to make us weary when it becomes dark outside, firms will frequently emphasise in their marketing that the top-off offered by a melatonin supplement is “natural.” However, many of their real doses significantly exceed what the body produces on its own, according to Cohen. “What we know is that giving a 20-year-old adult a very small amount of melatonin in the morning—say, a tenth of a milligramme or three tenths of a milligram—raises their levels up to normal nighttime levels,” Cohen adds. Popular over-the-counter supplements frequently promise to contain five or even ten milligrammes each dose. Given the erratic amounts discovered in Cohen’s study, a nighttime melatonin programme could contribute several times what the body is capable of producing.