Melatonin is a hormone your brain releases in the evening as light fades. It doesn’t knock you out; it tells your body that night has begun. That distinction explains most of what melatonin supplements can — and can’t — do.
Where it helps
- Jet lag. Taken at the right time, melatonin can help shift your body clock to a new time zone.
- Delayed sleep phase. For people whose natural rhythm runs very late, small doses taken in the early evening can help move it earlier.
- Some sleep onset problems. Studies show modest reductions in the time it takes to fall asleep — often minutes rather than hours.
Where it doesn’t help much
For typical insomnia — waking at 3am, lying awake with a racing mind — melatonin’s effect is small. It isn’t a strong sedative, and it doesn’t address the habits and stress that usually drive chronic insomnia.
Dose: less is often more
Many products contain 5–10mg, but research suggests far smaller doses (0.5–3mg) often work as well for timing purposes, with less next-day grogginess.
What’s actually in the bottle
In the US, melatonin is sold as a dietary supplement, so products aren’t checked by the FDA before sale. A 2023 study in JAMA tested melatonin gummies and found most were inaccurately labelled — the actual amount ranged from roughly 74% to 347% of what the label claimed, and some contained CBD not listed in the main dose. Choose products with third-party testing seals (such as USP or NSF).
Safety notes
Melatonin is generally considered safe for short-term use in adults. Side effects can include headache, dizziness and daytime sleepiness. Talk to a clinician before using it if you take blood thinners, blood pressure medication, diabetes medication or immunosuppressants, or if you’re pregnant. Keep gummies away from children — accidental ingestion has risen sharply.