Does melatonin actually help you sleep?
Melatonin modestly speeds up falling asleep and is genuinely effective for circadian problems like jet lag or shift work, but it does little to fix poor sleep quality or short duration once your clock isn't the issue.
Melatonin isn’t a sedative in the way Ambien or diphenhydramine are. It’s a hormone your pineal gland releases when it gets dark, telling your body nighttime has started. Taking it as a pill adds a timing signal, not a chemical knockout — and that distinction explains both where melatonin works and where it doesn’t.
For garden-variety insomnia — lying awake in your own bed, on your own schedule — the evidence is real but underwhelming. A widely cited meta-analysis of 19 trials found melatonin cut time to fall asleep by about 7 minutes and added roughly 8 minutes of total sleep, with a small bump in reported sleep quality. That’s a genuine, statistically real effect. It is not the difference between insomnia and a great night’s sleep, and in analyses restricted to adults without another sleep or psychiatric condition, the effect on total sleep time and efficiency sometimes disappears entirely.
Melatonin earns its reputation somewhere else: circadian misalignment, where your internal clock and local time disagree. For jet lag, a Cochrane review of ten trials called it “remarkably effective,” with a number-needed-to-treat around 2 for flights crossing five or more time zones. A separate review of shift workers found the same pattern — less daytime sleepiness, fewer awakenings, more total sleep. You’re not sedating yourself here; you’re correcting a clock that’s genuinely out of sync, which is a different and easier job.
Dosing is still being worked out
Most over-the-counter melatonin in the US comes in 3-10 mg doses, higher than the research supports. A 2024 dose-response meta-analysis found effects peaked around 4 mg/day, and that dosing roughly three hours before target bedtime outperformed the common practice of taking it thirty minutes before lights-out.
What’s actually in the bottle
Because melatonin sells as a supplement, not a regulated drug, quality control is inconsistent. A lab analysis of 31 products found actual content ranging from 83% below to 478% above the labeled dose, and about a quarter contained unlabeled serotonin. Lot-to-lot variation within the same product hit 465%.
Bottom line: treat melatonin as a jet-lag and shift-work tool first, taken at a low dose a few hours ahead of your target bedtime from a third-party-tested brand — not as a fix for ordinary bad sleep.