Among the most frequently reported problems people send the FDA about melatonin is one that stops you short: insomnia. The exact thing it's sold to fix turns up as the sixth most-common reaction in the reports. We found that going through all 652 melatonin adverse-event reports in the FDA's database, and it previews the larger point — melatonin isn't quite the uniformly gentle, harmless-if-it-doesn't-work supplement its "natural sleep aid" reputation suggests.
The usual caveat has to come first, because it governs everything below: these are reports of problems people experienced while taking melatonin, not proof it caused them, and the counts reflect how often something gets reported, not your personal odds. (We have a separate guide on reading these reports without being misled.) With that in mind, here's what 652 reports actually show.
Most reactions are mundane — and a few aren't
The bulk of melatonin's reported effects are the same ordinary complaints that dominate supplement data generally: nausea, diarrhea, vomiting, dizziness. Nothing exotic, mostly the stuff that makes for a bad night rather than an emergency.
But two stand out. Insomnia, as noted, is the sixth most-reported reaction — people taking a sleep aid and reporting that they couldn't sleep. And hallucination lands at number fourteen. Melatonin is a hormone that acts on the brain, and vivid dreams and nightmares are a recognized effect, but seeing it logged repeatedly as "hallucination" in federal reports is genuinely striking, and it shows up alongside anxiety in the top twenty. For a product marketed as gentle, the reported effects skew more neurological than you'd expect.
It's a hormone, not a vitamin
This is the reframe most people are missing: melatonin isn't a nutrient, it's a hormone your body produces — sold over the counter with no FDA pre-approval for safety, because supplements aren't regulated like medicines. One consequence is that the amount in the bottle isn't guaranteed; studies have repeatedly found the actual melatonin content of products, gummies especially, varying widely from what the label claims. That uncertainty matters most for the group the data flags hardest.
The pediatric signal is the one to watch
This is the clearest, most actionable finding in the dataset. Of the 652 reports, 49 involve children — including three toddlers under the age of two, where accidental ingestion is the near-certain explanation. Gummy melatonin looks and tastes like candy, and poison-control centers have reported steep increases in young children swallowing it.
And in the pediatric reports specifically, the reactions skew more alarming than in adults. Alongside vomiting, the children's reports include hallucination, convulsions, and aggression, plus several coded as overdose. None of that establishes that melatonin alone caused these — but the pattern is exactly what you'd worry about with a sweet-tasting hormone left within a child's reach.
For parents, the takeaways are the same as for any medicine: keep it up high and out of sight, don't present gummies as a treat, and talk to a pediatrician before giving melatonin to a child — many have real reservations about routine use in kids. If a child swallows a large amount, in the U.S. you can reach Poison Control any time at 1-800-222-1222.
A steady rise, not a scare
The report counts have climbed steadily over the years, with a clear bump in 2020 and a high-water mark around 2022–23. That isn't the fingerprint of a recall or a single bad batch — it tracks melatonin's mainstream boom, the pandemic-era surge in sleep supplements and the years of peak adoption that followed. More reports here mean more people taking it, not a product that suddenly turned dangerous. It's the counts-not-rates lesson in plain view.
About the serious end
Thirteen of the 652 reports involved a death. We include that the way we include it everywhere on this site: as a count, with the firm caveat that the FDA's database doesn't establish causation, and that reports like these almost always involve other medications or underlying health conditions. It's worth stating only because "natural sleep aid" branding can imply a product with no serious end of the spectrum at all — and the honest picture has more texture than that.
So, is melatonin safe?
For most adults, the reported problems are minor, and melatonin is taken by millions without incident — the data can't tell you your odds, and nothing here says otherwise. But the honest reading is more useful than a blanket yes. Melatonin is a hormone, not a candy; the dose in the bottle isn't guaranteed; some people report the opposite of the sleep they were after; and the data's sharpest signal is around children, where the right move is a conversation with a pediatrician and keeping the gummies locked away.
Look up the full melatonin breakdown on its data page, read it counts-not-rates, and take any concern to a doctor or pharmacist. "Natural" was never the same thing as "inert."