Sleep Experts Want You To Know This Shocking Fact About Melatonin Supplements

For those who have trouble falling asleep (read: most of us here in the U.S.), nightly sleep aids hold a certain appeal, with melatonin being one of the most popular. But there are a lot of myths and misconceptions about what supplemental melatonin can and can't do and how much of it should be taken at a time.

For this study, researchers analyzed 30 melatonin supplements purchased from local grocery stores in Canada (one of the few countries, in addition to the U.S., where melatonin is available without a prescription). They tested to see how the amount of melatonin in the supplement matched up to the amount listed on the bottle.

"Melatonin content was found to be highly variable between samples and lots, with no pattern observed between brand, form of supplement, labeled value, or presence of other herbal extracts," the study's result section reads. The actual amount of melatonin ranged from -83% to +478% across the samples tested—meaning that some had levels that were 478% higher than what was listed on the bottle (while others contained less melatonin than what was promised on the Supplement Facts label).

"Additionally, lot-to-lot variability within a particular product varied by as much as 465%," adds Ellen Wermter, FNP-BC, a family nurse practitioner and spokesperson for the Better Sleep Council.

While this study's findings are not exhaustive (do not encompass all melatonin supplement brands), all in all, say Graham and Wermter, this research presents yet another reason to be cautious when taking melatonin supplements. They recommend only using supplemental melatonin for a specific purpose (say, if you're traveling to a new time zone and want to adjust your sleep schedule accordingly) with a set time period in mind and from a reputable brand that prioritizes testing.