Chewing on sweetened gummies dosed with the hormone melatonin is a pre-bed ritual for many children across the US.
Considered a safe and convenient way to help tiny brains drift off into la-la land, the sleep aid is sold without the need for a prescription as a supplement, often in small bottles adorned by cute cartoons in bright colors.
An analysis of 25 unique melatonin gummy brands sold in the US found many, if not most, of those labels misrepresent the precise quantity of hormone they contain, with one having more than three times the reported dose.
The team of researchers from the Cambridge Health Alliance in Massachusetts and the University of Mississippi ran liquefied samples of the gummies through an ultra-high-performance liquid chromatography-photodiode array to determine levels of melatonin, cannabidiol (CBD), and serotonin. These were then compared with the listed ingredients and recommended servings.
Produced by the pineal gland when the lights go out, melatonin is the brain's way of preparing the body for sleep. In today's world of fluorescent globes and glowing screens, the triggers of darkness face some stiff competition, making it harder for most of us to sink into a restful slumber.
Throw in rising anxieties and other distractions, and it's little wonder that so many adults in the US are artificially pumping up their melatonin levels in the hopes of getting a good night's rest.
While there are few recent figures on the number of children routinely taking melatonin supplements, trends were on the rise pre- pandemic, with a reported 22 percent increase from 2013 to 2016 alone.
It's hard to say for sure just how much melatonin is required to encourage a typical body to shut down for the night. Studies regularly test dosages as high as 10 milligrams, though in most cases, somewhere from 1 to 5 milligrams is recommended for children between 5 and 15 years of age.
As might be expected, most of the brands tested featured labeled quantities of 3 to 5 milligrams per serving size, with a recommendation of up to two gummies per day.
Not all gummy brands target children, admittedly, with some products marketed as sleep and circadian rhythm support proclaiming contents of between 10 and 30 milligrams of cannabidiol (CBD), an ingredient that isn't approved for consumption by minors.
In truth, 22 of the 25 products analyzed were mislabeled. One didn't contain any melatonin at all, despite stating on the label that each dose had 3 milligrams of the hormone. Another brand contained 10 milligrams per serving instead of the 3 milligrams it claimed, a difference of 347 percent.
The first study of its kind in the US, the numbers echo a similar analysis conducted in Canada in 2017, which found melatonin concentrations varied by 17 percent to 478 percent of the labeled content. What's more, quantities ranged between servings within brands by as much as 465 percent.
Few adults might consider the precise amount of hormone in each bite-sized chew. That said, parents are certainly concerned by the potential for overdose, with the number of hospitalizations and calls to poison hotlines over pediatric melatonin ingestion skyrocketing in recent years.
It's hard to say whether their fears are unfounded. Melatonin clears from the body relatively quickly, for one thing. Tests on adult volunteers comparing doses of up to 100 milligrams with a placebo reported no differences or adverse effects.
Children's bodies can be different machines, however, with fine-tuned developmental processes at risk of disruption. Without long-term studies providing a clear answer one way or another, we're left to speculate based on a small amount of animal research hinting at possible influences on a range of body systems.
In the 2017 Canadian study, levels of serotonin – a neurotransmitter related to melatonin – were found in more than a quarter of the brands analyzed, posing much more concerning risks of potential health effects.
As usual, further research will help determine the risks that arise from misleading labeling. Understanding the processes that give rise to the discrepancy, and enforcing regulations, could help reassure the public that melatonin gummies contain precisely what's on the label.
That would go a long way to ensuring parents can sleep well at night with the knowledge they've made a sound choice for their children's health.
This research was published in JAMA.