Melatonin is a popular dietary supplement
If there is one aspect of the dietary supplement industry that both critics and fans should agree on, it’s that what’s on the label should accurately describe what’s in the bottle. Whether it’s a supplement, or an over-the-counter drug, consumers deserve health products manufactured to high standards. When it comes to ensuring the products we buy are of high quality, we’re largely reliant on regulation to protect us. Yes, there are independent organizations that test some products. But only a regulator can enforce production to consistent and strict quality standards. A weak regulatory framework, which doesn’t hold manufacturers to account, would be expected to result in a product of lower quality. And that’s exactly what you see when you look at supplements on the market today. A recent research letter in the Journal of the American Medical Association adds more evidence to established concerns about supplement quality in the United States.
Insomnia can be a persistent issue for both children and adults. Melatonin is a hormone that is sold without a prescription in many countries. It is widely perceived as safe and effective and many health professionals recommend it (despite mixed evidence) for treating sleeping problems in both adults and children. In the United States, sales of melatonin increased from $285 million in 2016 to $821 million in 2020 and continue to grow at 10% annually. With this growing popularity the number of pediatric poisonings reported to poison control centres has also increased. In 2020, melatonin also became the most frequently-reported pediatric poisoning reported.
What is melatonin?
In the early 1900s it was observed that the pineal gland secreted a substance with physiologic effects, and the hormone itself was named in 1958. Receptors for the hormone have been identified in the hypothalamus, the pituitary, and in other organs in the body. And it’s definitely a natural substance: melatonin is found in vertebrates, invertebrates, animals, bacteria, fungi, algae and plants. In humans and other mammals, melatonin secretion by the pineal gland follows the light cycle, being low during daylight hours, surging in the evening and peaking in the middle of the night. This secretion starts in infancy and continues through adulthood, followed by a decline as we age. It has been explored in clinical trials mainly for the prevention and treatment of sleep disorders like insomnia and jet lag. The evidence suggests melatonin is modestly effective. It seems to be most effective for sleep-onset insomnia, and may give a slight increase in total sleep time. In children melatonin may be recommended for long-term use in autism spectrum disorder and attention deficit hyperactivity disorder.
New quality concerns
Melatonin supplements in the United States are not subject to prescription drug manufacturing standards in the United States. The Dietary Supplement Health and Education Act of 1994 (DSHEA) established the regulatory framework for dietary supplements. It effectively excludes manufacturers of these products from virtually all regulations that are in place for prescription and over-the-counter drugs. Under DSHEA, the FDA may not approve dietary supplements for safety and effectiveness before they are marketed. The FDA can only intervene to pull products off the market, after they are marketed, and only if they are adulterated or misbranded.
In the absence of FDA oversight, a group of researchers undertook their own analysis of products available for sale:
In September 2022, products formulated as gummies with “melatonin” on the label were identified in the National Institutes of Health’s Dietary Supplement Label Database, the most comprehensive database of dietary supplements sold in the US.4 The 30 unique brands entered into the database in 2021 were purchased online. Products’ labels were examined after purchase and excluded if “melatonin” did not appear on the actual label.
The gummies were dissolved and then analyzed for the presence of melatonin, cannabidiol (a chemical isolated from cannabis) and serotonin, which has previously been found as a contaminant in melatonin products.
The results
Of the 30 products identified, four were unavailable for purchase and one product didn’t list “melatonin” on the label, leaving 25 products for analysis. One product contained no melatonin at all but contained 31.3mg of CBD. Among the remaining products, the actual quantity of melatonin ranged from 74% to 347% of the labelled content. For example, on product labelled to contain 3mg actually contained 10.4mg. Another labelled to contain 5mg contained only 3.7mg. Overall, 88% of the products where inaccurately labelled. Only 3 products contained melatonin that was +/- 10% of the labelled content.
Five products listed CBD as an ingredient. The quantity of CBD ranged from 104% to 118% of the labelled content – much better than the melatonin. Serotonin was not detected in any products.
Shopping in a market tilted again consumers
This analysis joins many others in pointing out serious quality concerns with dietary supplements. Based on this small sample of melatonin gummies, these products are not being manufactured to prescription-quality standards. The fact that these products are being used in children is concerning, given the potential for overdoses with poor quality products and unlabelled ingredients (i.e., CBD). Lax regulation has undoubtedly been a boon to manufacturers, leading to many products being marketed – but also making it harder for consumers to find products that are safe, effective and have high quality standards.