Melatonin: Does It Work, How Much, and How to Use It (2026)

What melatonin is

Melatonin is a hormone your brain makes when it gets dark. It helps set your body clock and the timing of sleep. Light at night can block it (NIH). Most melatonin supplements are made in a lab (NIH). In the US, melatonin is sold as a dietary supplement, so the FDA checks it less strictly than a drug. In several other countries you need a prescription for it (NIH).

What studies found, and what they didn’t

• Falling asleep: a small effect. A review of 19 studies with 1,683 people with sleep disorders found melatonin cut the time to fall asleep by about 7 minutes and added about 8 minutes of sleep. The authors call the effect “modest” and say it did not appear to fade with continued use (Ferracioli-Oda 2013).
• Long-term insomnia: not recommended. The American Academy of Sleep Medicine, a US sleep doctors’ group, suggests doctors not use melatonin for chronic insomnia in adults (AASM 2017). The recommendation is “weak”, which the group says does not mean it doesn’t work. NIH says there is not enough strong evidence to recommend it for chronic insomnia. If you have trouble sleeping most nights, see a doctor.
• Jet lag: studies found it may help. In 9 of 10 trials, melatonin taken near bedtime at the destination (10 pm to midnight) cut jet lag after flights across five or more time zones (Herxheimer 2002, a Cochrane review). NIH’s newer summary is more careful: melatonin “may help”, based on reviews from 2010 and 2014.
• A body clock that runs late: in studies of delayed sleep phase disorder (you can’t fall asleep until very late), people fell asleep about 23 minutes sooner on average, with adults and children counted together; the likely true figure was somewhere between 5 and 42 minutes (van Geijlswijk 2010). NIH says it appears to help, but it is not clear the benefits outweigh possible harms. This is a diagnosed sleep condition; ask a sleep doctor before using melatonin for it.
• Shift work: unclear. NIH says studies were small or inconclusive.

How long it takes to work: when blood levels peak

After a regular (not slow-release) dose, melatonin in the blood peaks about 50 minutes later, on average, though it varied a lot between studies (Harpsoe 2015). Trials gave it anywhere from 30 minutes to 4 hours before bed. See when to take it.

How much to take

Most trials used 0.5 to 5 mg; a few small ones used 0.3 mg. For jet lag, doses above 5 mg were no more effective (Herxheimer 2002). The NIH page we read gives no daily amount or upper limit. See how much to take, or read about 1 mg.

Side effects and cautions

NIH says short-term use appears safe for most people. Side effects in short studies were mild: headache, dizziness, nausea and sleepiness. Little is known about long-term use (NIH).

• Medicines: ask your doctor first if you take any medicine. NIH names epilepsy and blood thinners as needing a doctor’s care.
• Pregnancy and breastfeeding: there is little research on safety (NIH). Ask your doctor first.
• Older adults: melatonin may stay active longer and cause daytime drowsiness (NIH).
• Heart failure: a 2025 conference abstract, not a peer-reviewed paper, linked long-term use to heart failure. It cannot show melatonin was the cause. If you have heart disease, ask your doctor.

Read the full side effects guide, including whether melatonin is habit-forming.

Melatonin and children

Ask your child’s doctor before giving melatonin. NIH says the right dose, timing and long-term effects in children are not known. Calls to US poison centers about children and teens swallowing melatonin rose 530% from 2012 to 2021 (Lelak 2022). Keep melatonin, especially gummies, out of reach. Read more about children.

Why a testing list matters

Lab tests have found melatonin products with far less or far more melatonin than the label says (Erland 2017; Cohen 2023). In our view, a public testing list is the best outside check a buyer can see, though no study we read tested whether listed products are more accurate. 12 of the 29 melatonin products we read are on one. Two of these are sold through our links: Nature Made Melatonin 3 mg and Nature Made Melatonin 2.5 mg Gummies. See which are on a list, and what the tests found.

Which melatonin to buy

Our pick is at the top of the page. By need:

See the best melatonin, scored, or see what each one costs a night.

Melatonin guides

Sources

1. NIH National Center for Complementary and Integrative Health. Melatonin: What You Need To Know (last updated May 2024; read October 12, 2026).
2. Ferracioli-Oda E, et al. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013. PubMed 23691095. Partly funded by Eli Lilly research awards.
3. Sateia MJ, et al. Clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults (AASM). J Clin Sleep Med. 2017. PubMed 27998379
4. Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev. 2002. PubMed 12076414
5. van Geijlswijk IM, et al. The use of exogenous melatonin in delayed sleep phase disorder: a meta-analysis. Sleep. 2010. PubMed 21120122
6. Harpsoe NG, et al. Clinical pharmacokinetics of melatonin: a systematic review. Eur J Clin Pharmacol. 2015. PubMed 26008214
7. Heart failure: Nnadi, et al. Abstract 4371606. Circulation. 2025;152(Suppl 3). doi:10.1161/circ.152.suppl_3.4371606 (conference abstract, not peer reviewed as a paper).
8. Lelak K, et al. Pediatric melatonin ingestions, United States, 2012–2021. MMWR. 2022. PubMed 35653284
9. Erland LA, Saxena PK. Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content. J Clin Sleep Med. 2017. PubMed 27855744
10. Cohen PA, et al. Quantity of melatonin and CBD in melatonin gummies sold in the US. JAMA. 2023. PubMed 37097362

This page is for information. It is not medical advice.