Melatonin gummies in the US contain far more of hormone than listed

Most melatonin gummies sold in the US contain far more melatonin – a hormone produced naturally by the body that helps regulate circadian rhythms – than what is listed on labels. This increases the risk of overdosing, especially in children who may mistake the gummies for candy.

Melatonin supplements are generally considered safe, but high doses have been associated with serious side effects. Between 2012 and 2021, more than 27,000 adolescents in the US visited a healthcare facility after consuming too much melatonin, of which nearly 4100 were hospitalised.

Pieter Cohen at Cambridge Health Alliance in Massachusetts and his colleagues compared the contents of melatonin gummies to what is listed on their label. They identified 30 different melatonin gummy products sold in the US in 2021 using the National Institutes of Health’s Dietary Supplement Label Database, the most comprehensive database of dietary supplements sold in the US. Only 25 were available for purchase and mentioned melatonin on the label when the study was conducted in September 2022.

The researchers dissolved one dose of each of these products into a liquid, and then identified and quantified the chemical compounds in the sample. They found that of the 25 products, 22 were inaccurately labelled and contained between 74 and 347 per cent of the amount of melatonin listed.

Sanjeev Kothare at Northwell Health in New York isn’t surprised by these results given that melatonin is not a regulated substance in the US. Dietary supplements, like melatonin, receive minimal oversight from regulatory bodies in the US.

He says the findings are concerning though, as melatonin can cause seizures and respiratory failure at very high doses.

“Although [melatonin is] a medication, a hormone, it’s sold as a supplement,” says Cohen. So, it “can be sold without any information about the risk at a certain dose and can be formulated at any dose”, he says.