In a recent study, researchers analyzed 25 melatonin gummies that, according to their labels, each contained a dose between 1 and 10 milligrams (typically 3 to 5 mg).
Only three of the supplements turned out to be within 10 percent of what the label claimed.
In the other 22 supplements, the amount of melatonin ranged from 1.3 mg to 13.1 mg per serving. Most had 14 to 70 percent more melatonin than what was labeled. One brand had 10.4 mg instead of 3 mg. Another had none, though its label claimed to have 5 mg.
(The researchers only analyzed one sample from each brand, so it's possible that the results could differ in other samples from the same brands.)
What to do
Melatonin is a supplement, not a drug, so don’t assume that labels are accurate. (Whether it works is another question.) What's more, one study found that taking a mere 0.1 to 0.3 mg of melatonin raises blood levels to the normal range in young adults.
And keep all supplements away from children. Calls to U.S. Poison Control Centers about (mostly unintentional) melatonin ingestion in kids increased 5-fold between 2012 and 2021. Those calls were linked to 27,795 emergency department and clinic visits, 4,097 hospitalizations, 287 intensive care unit admissions, and two deaths.