What Is Melatonin Toxicity
Melatonin toxicity refers to adverse effects from doses exceeding the body's typical signaling range, often above 5 mg per day for adults. Most over-the-counter supplements contain 1 mg to 10 mg, yet many products contain mislabeled amounts. The FDA classifies melatonin as a dietary supplement, not a drug, so it does not approve or set potency standards before sale. In 2023, independent testing by LGC, a UK-based laboratory, found that 26 percent of melatonin supplements contained serotonin, a related compound that can cause toxicity even at low doses. The American Academy of Sleep Medicine does not recommend melatonin for chronic insomnia without medical supervision, citing inconsistent product quality and limited long-term safety data American Academy of Sleep Medicine.
Common Doses, Side Effects, and At-Risk Groups
Typical supplement doses range from 0.5 mg to 5 mg, with some products marketed at 10 mg or higher. Clinical trials often use 0.3 mg to 5 mg for sleep onset, and higher doses do not consistently improve efficacy but increase side effects. Reported side effects include headache, dizziness, nausea, daytime drowsiness, and vivid dreams. In children, accidental ingestion of high-dose gummies has led to emergency department visits, with the American Association of Poison Control Centers noting a rise in pediatric melatonin exposures during the 2010s and early 2020s. People taking blood thinners, diabetes medications, or immunosuppressants face higher interaction risks, and those with autoimmune conditions should consult a clinician before use National Center for Complementary and Integrative Health.
Regulatory Landscape and Recent Oversight Actions
FDA Stance and Supplement Regulation
Under the Dietary Supplement Health and Education Act of 1994, melatonin products do not require premarket approval, and the FDA does not test them for purity or label accuracy before sale. In 2022 and 2023, the FDA issued warning letters to several supplement manufacturers for mislabeling and contamination. The agency advises consumers to look for third-party testing seals from organizations such as USP, NSF International, or ConsumerLab. In parallel, the European Medicines Agency and national agencies in Australia and Canada have classified melatonin as a prescription or pharmacist-supervised medicine for certain indications, reflecting stricter controls than the U.S. framework U.S. Food and Drug Administration.
Market Size and Key Players
The global melatonin market was valued at roughly $800 million in 2022 and is projected to grow through 2030, driven by sleep-disorder prevalence and supplement adoption. Major retailers such as Amazon, Walmart, and CVS sell private-label and brand-name melatonin, while compounding pharmacies offer customized formulations. In 2023, the Council for Responsible Nutrition reported that melatonin ranked among the top three sleep-aid ingredients in U.S. supplement sales. Companies such as Nature Made, NOW Foods, and Solgar market melatonin products with third-party quality seals, while newer direct-to-consumer brands emphasize low-dose formats U.S. Securities and Exchange Commission.