When The Medical Letter discusses dietary supplements of one sort or another, we often end by urging our readers to tell their patients not to take them because we really don’t know what’s in them. A Research Letter in a recent issue of JAMA on the quantity of melatonin in melatonin gummies gives us an always-welcome opportunity to say we told you so.1 Melatonin has not been approved for any indication by the FDA and given its ready availability without a prescription on the shelves of CVS, Walgreens, etc., it is possible that no pharmaceutical manufacturer will ever find it worthwhile to seek FDA approval for the drug.
The Research Letter begins with the alarming information that 1.3% of children in the US use melatonin, which I guess means they take it regularly. And some of the products they take, particularly gummies labeled as sleep aids, also contain cannabidiol (CBD). The authors of the Research Letter analyzed the contents of 30 brands of gummies identified in the National Institute of Health’s Dietary Supplement Label Database as containing melatonin. One of these products did not contain detectable levels of melatonin but did contain 30 mg of cannabidiol. The other products contained from 74% to 347% of the labeled quantity (usually 3 or 5 mg) of melatonin. Products labeled as containing CBD came closer (104% to 118%) to containing the labeled amount. The authors also analyzed the gummies for serotonin but found none. They did not look for anything else.
The Medical Letter has published an article on the use of melatonin to treat insomnia in children.2 We found that up to 50% of normal children and up to 80% of those with autism spectrum disorder (ASD) or attention-deficit hyperactivity disorder (ADHD) have sleep disturbances. No drugs have been approved by the FDA for treatment of insomnia in children. A systematic review of 19 randomized controlled trials of melatonin for chronic sleep problems in children and adolescents, including many with ASD or ADHD, found that melatonin reduced sleep latency (range 11-51 minutes), increased sleep duration (range 14-68 minutes), and decreased wake time after sleep onset (range 12-43 minutes), but did not reduce the number of awakenings per night. Improvement in sleep with melatonin was greatest in children with neurodevelopmental disorders.3
We have also published an article on cannabis and cannabinoids, including CBD.4 Unlike tetrahydrocannabinol (THC), which is the main psychoactive constituent of marijuana, CBD does not produce intoxication or euphoria. It is FDA-approved for use in children for treatment of seizures associated with Lennox-Gastaut Syndrome or Dravet Syndrome. There is no acceptable evidence that CBD is effective for treatment of insomnia in children or adults.
There is a lot we don’t know about use of melatonin for treatment of insomnia in children. For starters, we don’t know the optimal dose or timing of administration. And melatonin has many functions other than synchronization of sleep. It has effects on bone cell proliferation, immune responses, sexual maturation, and more. We have no data whatsoever on the safety of long-term use of melatonin in growing children. Given all the unknowns, including the purity and potency of melatonin products, is it worth the risk? I don’t think so.
- PA Cohen et al. Quality of melatonin and CBD in melatonin gummies sold in the US. JAMA 2023; 329:1401. doi: 10.1001/jama.2023.2296
- Melatonin for insomnia in children. Med Lett Drugs Ther 2020; 62:103.
- MS McDonagh et al. Pharmacologic treatments for sleep disorders in children: a systematic review. J Child Neurol 2019; 34:237. doi: 10.1177/0883073818821030
- Cannabis and cannabinoids. Med Lett Drugs Ther 2019; 61:179.
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Thank you for your reminder about the limitations of knowledge when using these products and their safety; especially considering their use with the developing brain.