Melatonin label accuracy was poor in a 2023 lab study of gummy products sold in the United States. Of 25 products tested, 22 did not match their labels. This piece explains what the study did, what it found, and what a buyer can check.
What the study tested
The work is a research letter in JAMA, published April 25, 2023. It was led by Pieter Cohen of Cambridge Health Alliance, with lab partners at the University of Mississippi. The title is "Quantity of Melatonin and CBD in Melatonin Gummies Sold in the US."
The team looked in the National Institutes of Health Dietary Supplement Label Database in September 2022. They searched for gummies with "melatonin" on the label. That gave 30 unique brands that had been entered in the database in 2021. Four were not available to buy, and one did not show "melatonin" on the actual label. That left 25 products for the lab.
The lab dissolved the gummies and measured melatonin, CBD, and serotonin with a method called ultra high-performance liquid chromatography. Serotonin was on the list because an earlier study had found it in some melatonin products.
What it found
The gap between label and lab was large. In the products that held melatonin, the measured amount ran from 74 percent to 347 percent of the labeled amount. Only 3 of 25 products, or 12 percent, landed within 10 percent of what the label said. The other 22, or 88 percent, did not.
One product had no melatonin that the lab could detect. It did contain CBD, a compound that U.S. rules do not allow in a dietary supplement. Five products listed CBD on the label. For those, the measured CBD ran from 104 percent to 118 percent of the label. No product had detectable serotonin.
The authors gave a reason for the focus on gummies. Children may eat them on purpose or by accident. The letter notes that calls to U.S. poison control centers about children and melatonin rose 530 percent from 2012 to 2021.
What the study cannot tell you
It was a small letter, not a market survey. It tested 25 products, and it did not say how many gummies or lots were tested per brand. A different lot of the same brand could land closer to its label or farther from it. The study also covered only gummies. It does not speak for tablets, capsules, or liquids.
The authors used a 10 percent window as their line for an accurate label. That is a choice, and a reader can weigh it. Still, a range from 74 to 347 percent is wide under any window.
The study named brands by code only. So the paper gives you a pattern, not a list of brands to avoid.
Why a supplement label is not a guarantee
The FDA says it does not approve dietary supplements before they are sold. It also says it generally does not approve supplement claims or other labeling before use. The firm that makes or sells the product is responsible for making sure it is not misbranded.
The FDA also says its rules require makers to follow current good manufacturing practices. These are meant to help ensure the identity, purity, quality, strength, and composition of a supplement. A rule on paper is not the same as a test of every lot, which is the point the JAMA letter makes.
The Supplement Facts panel must list the serving size and the amount of each dietary ingredient per serving. That is the number the lab checked against.
What a buyer can check
You cannot test a gummy at home. You can read the label with care and ask a few plain questions.
First, find the Supplement Facts panel. Check the serving size, since a serving may be more than one gummy. Check that the amount of melatonin is stated and that it matches the front of the pack.
Second, look for a mark from an outside testing group, and read its exact wording. A mark that names the product and the group is stronger than a vague phrase such as "lab tested." Our earlier explainer on supplement seals covers what the two best known marks check.
Third, look at the expiration or lot information on the pack. If a brand will share a certificate of analysis for your lot, ask for it. A brand that cannot say who tested the lot, or how, has told you something.
Fourth, keep these products away from children, and store them like any other item a child should not reach. This is basic safety advice and not medical advice. For questions about your own use, ask a pharmacist or doctor.