If you’ve taken to melatonin to help you sleep, be aware that you may not be getting what the bottle label says is inside. A Research Letter in the Journal of the American Medical Association in April highlighted yet again how such dietary supplements are not regulated the way pharmaceuticals are and may pose dangers, especially to children, if they contain higher amounts of ingredients or undisclosed substances.
Researchers at Cambridge Health Alliance in Massachusetts and the University of Mississippi purchased 25 different brands of melatonin gummies online in September 2022 and then tested them for the presence and quantity of melatonin and other substances (both declared and not declared on the labels).
Melatonin is a hormone produced by the pineal gland in the brain at night. It is involved in regulating the sleep-wake cycle and is commonly used in synthetic form as a remedy for sleep-related problems including insomnia and jet lag—though evidence of its effectiveness as a supplement is mixed.
Of the 25 products tested, 24 contained melatonin in amounts ranging from 1.3 to 13.1 milligrams per serving—which was 74 to 347 percent of the amount claimed on the labels. One product had no detectable melatonin at all. Overall, 22 products (88 percent) were not labeled correctly, and only 3 (12 percent) came within 10 percent of the claimed amount of melatonin.
For gummies that also listed CBD (cannabidiol, another substance promoted for sleep), the actual amount of that ingredient ranged from 104 to 118 percent of what was listed on the label. The researchers also tested for serotonin, a hormone related to melatonin that has previously been detected in melatonin supplements, but did not find any supplements with undisclosed amounts.
A Canadian analysis of melatonin products, published in the Journal of Clinical Sleep Medicine in 2017, similarly found that most were inaccurately labeled, with quantities of melatonin ranging from as little as 17 percent to as much as 478 percent of the declared amounts.
The authors of the current analysis noted that it takes only 0.1 to 0.3 milligrams of melatonin to increase blood concentration to normal nighttime levels in young adults, and that consuming the supplements as directed could provide 40 to 130 times above that amount. During the pandemic, more people including children used melatonin to combat stress and sleep problems, and, according to the CDC, incidences of melatonin ingestion reported to U.S. poison control centers rose 530 percent between 2012 and 2021 in children, with concomitant increases in emergency room visits and hospitalizations.
Some study caveats: The researchers tested just a single sample of each brand of melatonin and only gummy formulations. It’s not known how their results would generalize to other melatonin supplements, including tablets and capsules, or whether the content of melatonin and other substances may vary across batches from the same manufacturer.
BOTTOM LINE: In light of loose government oversight of dietary supplements and study findings of wildly inaccurate labels, it behooves consumers to assess their true need for these products and how effective they are. There are no guarantees of quality or effectiveness, but if you decide to take melatonin or other supplements, you might ask your pharmacist to recommend a brand (rather than buying blindly on the internet) or look for supplements with USP-verified labels or those that pass muster by the private supplement-testing company ConsumerLab.com. And remember to keep all products, whether labeled for adults or children, out of reach of kids’ hands.
