Researchers concluded 22 of 25 gummy supplements were “inaccurately labeled” and often contained more melatonin than advertised.

The chewy melatonin gummies that many people take before bedtime to promote sleep may contain far more of the hormone than what’s printed on the label, according to a study published in the medical journal JAMA on Tuesday.

A group of scientists examined 25 brands of melatonin gummy products and discovered that 22 of them contained varying levels of melatonin than what was stated on their labels. One contained only 74 percent of the advertised amount of melatonin yet another product contained no detectable melatonin at all.

“One product contained 347% more melatonin than what was actual listed on the label of the gummies,” said study co-author Pieter Cohen, an associate professor of medicine at the Cambridge Health Alliance in Somerville, Massachusetts.

Researchers tested gummies from only a single bottle of each product, so it’s possible that the amount of melatonin varied from batch to batch. But the findings point to a staggering discrepancy between the amount of melatonin consumers think they’re ingesting and how much they might actually take, Cohen added. 

This study examined only gummies and focused on products sold in the United States but previous research has highlighted just how varied the quality of melatonin products can be. A 2017 study in Canada found that one melatonin supplement contained more than 400 percent of the amount listed on the label.

Consuming a gummy that unknowingly contains extremely high levels of melatonin — well over the daily 0.5 to 1 milligram per night that has been shown to induce sleep in kids — is also dangerous, researchers warned.

Melatonin use in children can cause drowsiness, headaches, agitation, and increased nighttime bedwetting or urination. There is also the possibility of harmful interactions with medications and allergic reactions to melatonin, according to the National Center for Complementary and Integrative Health, a division of the US National Institutes of Health.

The agency also warns supplements could affect hormonal development, “including puberty, menstrual cycles, and overproduction of the hormone prolactin,” which causes breast and milk development in women.

How much melatonin can adults take?

According to David N. Neubauer, who is an associate professor of psychiatry and behavioural sciences at Johns Hopkins University, if someone is considering trying melatonin, he suggests beginning with a dosage range of 1 to 3 milligrams.

“Take it prior to your bedtime because once you’re getting into bed it’s too late,” Neubauer told Washington Post.

The brain naturally produces the hormone and gradually releases more melatonin as people approach their natural bedtime. The hormone works with the body’s biological clock and “reinforces our circadian rhythm” to help someone feel ready for bed,

The body’s natural production of melatonin increases as an individual approaches their usual sleep time, and this hormone collaborates with the body’s biological clock to strengthen “the circadian rhythm”, ultimately promoting a feeling of readiness for sleep, he added.

Experts say that melatonin supplements can serve as a useful temporary remedy for individuals who are traveling across different time zones or individuals who prefer staying up late but want to adjust their sleeping patterns. Although there is limited scientific proof regarding the efficacy of melatonin in treating chronic insomnia, a considerable number of people still opt for it as it is considered to be a safe and non-addictive solution.

Pregnant or breastfeeding women should not take melatonin, according to Johns Hopkins University Medicine.

Is it safe for children to take melatonin?

Melatonin may promote sleep in children with certain neurodevelopmental disorders such as autism or attention-deficit/hyperactivity disorder, according to the American Academy of Pediatrics. 

But since melatonin is a hormone, experts say there are some concerns that regular use of the supplement could affect a child’s development, especially during puberty.

The American Academy of Pediatrics advises parents to consult a paediatrician and proceeding “cautiously and carefully.”