A Melatonin Study Highlights a Lack of Supplement Regulation

JAMA recently published a research letter highlighting the lack of supplement regulation by comparing the amount of melatonin and CBD in varying brands of melatonin gummies. The researchers determined that most melatonin gummies are inaccurately labeled with the wrong dose.

For this analysis, the researchers ordered 30 different brands of melatonin gummies identified in the National Institutes of Health Dietary Supplement Label Database. This database is the closest to a comprehensive compilation of dietary supplements in the United States, including melatonin supplements.

The brands were picked and ordered online based on information in the database as of September 2022. All the brands analyzed were entered into the NIH records in 2021; however, when the shipments arrived, the investigators used their criteria to determine the gummy classification. Any gummies without melatonin on the label were excluded.

After excluding those not labeled with melatonin and any gummies unavailable for purchase online, there were 25 brands left for analysis. Gummies from each brand were dissolved in a mixture of ethanol and acetonitrile–methanol. Samples of the aqueous solution were analyzed for melatonin, CBD, and serotonin concentrations using ultra-high-performance liquid chromatography-photodiode array analyses.

One of the samples did not even have any detectable traces of melatonin. The same brand had 31.3 mg of CBD.

Although all the other samples did contain melatonin, the concentrations varied dramatically, ranging from 1.3 to 13.1 mg per serving. Beyond various concentrations across brands, very few brands had accurately labeled concentrations. According to the publication, the actual concentration of melatonin was between 74% and 347% of what was written on the label, with only three products falling within 10% of the label quantity.

While no serotonin was detected in any gummies, five had quantifiable amounts of CBD, ranging from 10.6 to 31.3 mg. Although all the products declared CBD as an ingredient, the concentration was 4–8% greater than what was written on the label.

Melatonin is one of the most widely used dietary supplements. A recent study even noted that correct dosages of melatonin could reduce self-harm injury risk in pediatric patients. However, it is clear that dietary supplements could benefit from more oversight and monitoring.

“The great majority of melatonin gummy products were inaccurately labeled, with most products exceeding the declared amount of melatonin and CBD. To our knowledge, this is the first US study to quantify melatonin in over-the-counter melatonin products. A Canadian study had similar results: analysis of 16 Canadian melatonin brands found that the actual dose of melatonin ranged from 17% to 478% of the declared quantity,” noted the researchers in the study.

“Given these findings, clinicians should advise parents that pediatric use of melatonin gummies may result in ingestion of unpredictable quantities of melatonin and CBD,” they added.

The data from this study should be followed by additional in-depth analyses of melatonin and various other over-the-counter dietary supplements.