Consumers reaching for over-the-counter sleep aids may be taking far more—or occasionally far less—hormone than the package indicates. A 2023 peer-reviewed analysis published in the Journal of the American Medical Association (JAMA) revealed that out of 25 melatonin gummy products sold in the United States, 22 (88%) were inaccurately labeled. In the products that contained melatonin, the actual measured hormone content ranged from 74% to 347% of the dosage listed on the bottle, according to Dawn Peek and MedPage Today.

Led by Dr. Pieter Cohen of the Cambridge Health Alliance in Somerville, Massachusetts, the research team evaluated 25 gummy brands purchased online that were listed in the National Institutes of Health's Dietary Supplement Label Database. Only three of the 25 tested products contained melatonin quantities within 10% of their declared label claims. While these findings highlight significant quality control disparities among sampled gummy supplements, researchers note that the limited 25-product sample does not establish a market-wide estimate for all melatonin tablets, capsules, or liquid formulations.

Inside the Laboratory Findings

To determine how closely retail sleep aids matched their nutritional facts panels, investigators tested a single sample from each of the 25 gummy brands for melatonin, cannabidiol (CBD), and serotonin. Among the 24 products that held detectable levels of melatonin, actual quantities ranged from 1.3 mg to 13.1 mg per serving, as reported by Health Perk and AARP.

One tested product contained no detectable melatonin at all, delivering 31.3 mg of CBD instead. Across five products in the sample that explicitly declared CBD as an ingredient, the measured CBD levels ranged from 104% to 118% of the listed amount. Unlike an earlier Canadian investigation, no serotonin was detected in any of the 25 U.S. gummy products analyzed in the 2023 JAMA report.

These U.S. findings differ in scope from an earlier 2017 study that frequently appears in discussions of sleep supplement accuracy. According to Nutrition Pro, that 2017 analysis evaluated 31 melatonin supplements sold in Canada and found actual hormone content ranging from 83% below to 478% above the labeled dosage. The Canadian researchers also documented lot-to-lot variations as high as 465% between different batches of the same product and identified serotonin—a regulated neurotransmitter and breakdown byproduct—in eight of the 31 tested supplements. Because the 2017 study examined products in a different country across multiple delivery forms, public health analysts separate its numbers from the 2023 U.S. gummy investigation.

Why Supplement Labels Vary and the Question of Morning Grogginess

In the United States, melatonin is regulated as a dietary supplement under a framework dating back to 1994 rather than as an over-the-counter or prescription drug. Under U.S. Food and Drug Administration (FDA) rules, the agency does not test or approve dietary supplements for safety, effectiveness, or label accuracy before they reach store shelves. Manufacturers are legally responsible for ensuring their products meet federal standards, while the FDA exercises oversight primarily after products are already on the market. Noticeable variations in gummy products often stem from manufacturing challenges, where manufacturers may add excess active ingredients to account for degradation during shelf life or struggle to mix compounds evenly across gelatin or pectin batches.

For consumers, taking a gummy that secretly packs more than triple the listed hormone dosage raises practical questions about daytime side effects, particularly next-morning grogginess. Melatonin is a neurohormone naturally produced by the brain's pineal gland in response to darkness to help regulate the body's circadian rhythm. When adults or children inadvertently consume doses as high as 13.1 mg instead of a standard low dose, consumers and clinicians often hypothesize that lingering hormone levels may contribute to morning drowsiness or headaches.

However, medical researchers emphasize an important distinction: the 2023 JAMA study and the 2017 Canadian study strictly measured chemical content in laboratory settings. Neither study evaluated human subjects or proved a direct clinical link between mislabeled gummies and morning grogginess. While excess melatonin intake remains a plausible explanation for daytime fatigue, that connection represents a consumer concern rather than a demonstrated finding of the product-testing studies.

Rising Pediatric Exposures Prompt Public Health Warnings

The 2023 laboratory analysis was directly prompted by a sharp rise in childhood supplement exposures across the United States. According to the Centers for Disease Control and Prevention (CDC), U.S. poison control centers received reports of 260,435 pediatric melatonin ingestions between 2012 and 2021. Over that decade, annual reported ingestions among children rose by 530%, climbing from 8,337 calls in 2012 to 52,563 in 2021.

While 84.4% of the children involved in those reported cases showed no symptoms, the CDC documented 27,795 healthcare facility visits, 4,097 hospitalizations, 287 intensive care unit admissions, and two deaths tied to pediatric melatonin ingestions over the 10-year period. Approximately 94.3% of the exposures were unintentional, frequently involving children aged 5 and younger who accessed candy-like gummy bottles left within reach at home.

Frequently Asked Questions

Does the 347% maximum finding mean all melatonin supplements contain triple their listed dose?

No. The 347% figure was the highest disparity found among a limited sample of 25 U.S. gummy products tested in the 2023 JAMA study, which spanned from 74% to 347% of labeled amounts. Only one sample per brand was tested, meaning the results cannot be automatically generalized to all supplement brands, production batches, or non-gummy formats like tablets and liquids.

How are melatonin supplements regulated in the United States?

Melatonin is sold as a dietary supplement in the U.S., meaning the FDA does not test or approve products before they are sold to the public. While the FDA can take enforcement action if a marketed supplement is shown to be unsafe or misbranded, the agency does not conduct routine pre-market laboratory verification of dosage labels. Additionally, the FDA notes that including CBD in foods or labeling it as a dietary supplement is unlawful under federal rules.

What can consumers do to reduce the risk of inaccurate dosing?

Healthcare professionals advise consulting a physician or pediatrician before starting melatonin, especially for children. When purchasing over-the-counter supplements, clinicians often suggest looking for products that carry verification seals from independent third-party testing organizations—such as U.S. Pharmacopeia (USP)—which audit manufacturing facilities and verify that bottle contents match label claims. All sleep aids, particularly flavored gummies, should be stored in child-resistant containers out of the sight and reach of young children.

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