Supplements · 4 min read ·

Melatonin: better for jet lag than for insomnia

Melatonin is the best-known over-the-counter “sleep” pill. Its effect on falling asleep is small — but it works well for jet lag.

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In a nutshell

1What melatonin is

Melatonin is a hormone the body makes itself that regulates the sleep-wake cycle. Supplements contain a synthetic form of it.6

2Does it help you fall asleep?

Moderate evidence −7 min A summary of 19 trials with 1,683 people with sleep disorders: melatonin shortened the time to fall asleep by 7 minutes and lengthened sleep by 8 minutes; sleep quality improved slightly. Longer use and higher doses had larger effects.1
Moderate evidence 4 mg A summary of 26 randomised trials: the effect on falling asleep and sleep length grew with dose up to 4 mg a day. According to the authors, taking it about 3 hours before the planned bedtime may work better than the usual 30 minutes.2

3Jet lag

Strong evidence — Cochrane 9 of 10 A review of 10 trials: in 9 of them, melatonin taken at the destination close to bedtime (10 pm to midnight) reduced jet lag after flights across 5 or more time zones. Doses of 0.5–5 mg worked similarly; after 5 mg people fell asleep faster, and higher doses did not help more.3

4Safety and quality

Moderate evidence 37 studies A review of 37 randomised trials: adverse effects were uncommon and mostly mild — most often daytime sleepiness, headache and dizziness. But most trials lasted 4 weeks or less.4
Weak evidence — analysis of 31 products −83 to +478% An analysis of 31 supplements: melatonin content differed from the label by −83% to +478%, and in more than 71% of products by more than 10%. Eight also contained serotonin.5

Keep melatonin out of children’s reach: in the US, the number of cases of children swallowing it rose by 530% in 10 years.6

What to take from this

Sources

Written on , based on studies available at that date. Newer research may change the conclusions.

  1. Ferracioli-Oda E., Qawasmi A., Bloch M. H. (2013). Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One 8:e63773. doi.org/10.1371/journal.pone.0063773
  2. Cruz-Sanabria F. et al. (2024). Optimizing the time and dose of melatonin as a sleep-promoting drug: a systematic review of randomized controlled trials and dose-response meta-analysis. J Pineal Res 76:e12985. doi.org/10.1111/jpi.12985
  3. Herxheimer A., Petrie K. J. (2002). Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev CD001520. doi.org/10.1002/14651858.CD001520
  4. Besag F. M. C. et al. (2019). Adverse events associated with melatonin for the treatment of primary or secondary sleep disorders: a systematic review. CNS Drugs 33:1167–1186. doi.org/10.1007/s40263-019-00680-w
  5. Erland L. A. E., Saxena P. K. (2017). Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content. J Clin Sleep Med 13:275–281. doi.org/10.5664/jcsm.6462
  6. Lelak K. et al. (2022). Pediatric melatonin ingestions — United States, 2012–2021. MMWR Morb Mortal Wkly Rep 71:725–729. doi.org/10.15585/mmwr.mm7122a1

This is general information and does not replace a doctor. If you are pregnant or breastfeeding, for children, and if you take sleeping pills, blood thinners or epilepsy medicines, talk to a doctor about melatonin.