TL;DR — The short version
  • Melatonin helps you sleep earlier — not necessarily better
  • Best for jet lag, shift work, and going to bed later than you want
  • Most tablets are 5–10mg. The dose that actually works in studies is 0.5–1mg
  • 22 out of 25 melatonin gummies tested in a 2023 JAMA study had the wrong dose on the label
  • For general insomnia, therapy (CBT-I) works better and lasts longer

What melatonin actually does

Melatonin is a hormone your brain makes when it gets dark. Its job is to tell your body that night is coming — not to knock you out. Think of it as a clock signal, not a sleeping pill.

Your brain naturally makes about 0.1–0.3mg of melatonin per night. A standard pharmacy tablet? Usually 5mg or 10mg. That's up to 100 times more than your body would ever produce on its own.

What it's good for

Jet lag is where melatonin shines. Take 0.5–1mg at your target bedtime in the new time zone and it helps your body clock reset faster. Studies consistently back this up, especially for eastward travel.

Shift workers with changing schedules can also benefit — melatonin helps anchor sleep to whatever time they need to rest.

Night owls who naturally fall asleep at 2–3am can gradually shift their bedtime earlier using low-dose melatonin, taken a few hours before target sleep time.

A 2013 meta-analysis of 19 trials found melatonin cut the time to fall asleep by about 7 minutes on average. Not dramatic, but real.

What it's not so good for

If you just can't sleep — you lie awake, mind racing, waking at 3am — melatonin probably won't fix that. It barely outperforms a placebo for general insomnia. It also doesn't improve the quality of your sleep once you're asleep. You might drop off a few minutes sooner, but your deep sleep and REM stay roughly the same.

The other issue is dose. A 2023 JAMA study tested 25 melatonin gummies and found that 22 had the wrong amount on the label — some had nearly 3.5 times more than advertised. So even if you pick a "low dose" product, you often can't be sure what you're actually taking.

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Works well for
  • Jet lag — resetting after time zone changes
  • Shift workers with changing schedules
  • People who go to bed too late and want to shift earlier
  • Short-term use around travel or disrupted routines
  • Not addictive — you can stop without rebound insomnia
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Doesn't work well for
  • General insomnia — barely better than placebo
  • Improving deep sleep or dream sleep quality
  • High doses — more isn't better, and labels are often wrong
  • Long-term nightly use — evidence is thin beyond 13 weeks
  • Chronic sleep problems — therapy (CBT-I) beats it

The dose problem

This is the part most people get wrong. The dose that shows up in clinical research — the one that actually works — is between 0.5mg and 1mg. Most products in pharmacies start at 3mg and go up to 10mg or even 20mg.

Taking more doesn't help you sleep better. It might actually make your brain less sensitive to melatonin over time. If you want to try it, look for the lowest dose available, or cut a tablet.

0.1–0.3mg
What your brain naturally makes each night
0.5–1mg
What studies actually use — and what works
3–10mg
What most pharmacy products contain — far more than needed

What works better for insomnia

If you struggle to sleep regularly — not just when travelling — the most effective treatment isn't a supplement. It's a structured programme called CBT-I (Cognitive Behavioural Therapy for Insomnia). It's been tested head-to-head against sleeping pills and wins, both short and long term. It works by changing the habits and thought patterns that keep you awake. Your GP can refer you, or you can access it through apps like Sleepio.

Bottom line

Melatonin is useful for shifting your body clock — jet lag, night-shift schedules, going to bed too late. It's not a great general sleep aid. If you use it, take the smallest dose you can find (0.5–1mg) about 30 minutes before you want to sleep. For anything beyond occasional use, it's worth talking to your doctor.

References
  1. Ferracioli-Oda et al. (2013). Meta-Analysis: Melatonin for the Treatment of Primary Sleep Disorders. PLOS ONE. View →
  2. Cohen et al. (2023). Quantity of Melatonin and CBD in Melatonin Gummies Sold in the US. JAMA, 329(16). View →
  3. Erland & Saxena (2017). Melatonin Supplements: Significant Variability of Melatonin Content. J. Clinical Sleep Medicine, 13(2). View →