Melatonin for Sleep: Dosage, Timing, and Side Effects
Melatonin is the most misunderstood sleep aid. People treat it like a sedative; it's actually a clock signal. Used right, it helps you shift when you sleep — not how deeply you sleep.
What melatonin actually does
Your brain makes melatonin in darkness; it tells your body "night is here." A supplement nudges that signal. It helps with timing (jet lag, shift work, DSPD) far more than with falling asleep per se.
Dosage: lower is often better
Many studies use 0.5–3 mg, taken 30–60 minutes before desired sleep. The mega-doses (5–10 mg) common on shelves can cause next-day grogginess without extra benefit. More is not stronger here.
Timing is everything
Taking it too early or too late misses the window. For eastbound jet lag or phase shifts, the exact hour matters — a jet-lag calculator can map light and melatonin timing to your route.
Time melatonin with the Jet Lag Calculator →
Frequently asked questions
Is melatonin safe to take every night?
Yes at low doses (0.3-0.5 mg) for most adults. Higher doses (3-10 mg, common in supplements) are likely overkill — your body makes about 0.1 mg naturally, and the receptors respond to physiological doses. Long-term safety at low doses is well established.
How much melatonin should I take?
Start with 0.3-0.5 mg, taken 30-60 min before desired sleep time. Most supplements sell 3-10 mg — that's 10-30x what most adults need. Higher doses don't help and may cause morning grogginess.
Does melatonin help you fall asleep or stay asleep?
Primarily helps with sleep onset. It's less effective for staying asleep. If your issue is waking at 3 a.m., the cause is more likely cortisol/light exposure — not melatonin deficiency.
Can I become dependent on melatonin?
No. Melatonin is not habit-forming in the traditional sense, but your body may down-regulate its own production slightly with long-term high-dose use. Low-dose (0.3-0.5 mg) is unlikely to cause this.
When should I stop taking melatonin?
If you're using it for jet lag, 3-5 days after arrival is enough. For circadian phase disorders (DSPS), it can be used long-term under medical guidance. For general "I want to sleep better," use it as a 2-4 week bridge while you build better sleep habits.
References
- Buscemi, N., et al. (2006). Efficacy and safety of exogenous melatonin for secondary sleep disorders and sleep disorders accompanying sleep restriction: meta-analysis. BMJ, 332(7538), 385–393.
- NIH National Center for Complementary and Integrative Health. (2024). Melatonin: What You Need To Know. nccih.nih.gov.