What is melatonin?

Melatonin is a hormone that signals biological night and helps regulate the circadian sleep-wake rhythm. It is better described as a timing signal than as a strong sedative.

Melatonin is commonly included in sleep-support products.

Does it improve sleep?

Melatonin can produce modest improvements in sleep onset. A 2023 meta-analysis found that prolonged-release melatonin reduced sleep-onset latency by approximately five to six minutes compared with placebo. Effects on overall sleep quality and duration are less consistent.

Persistent insomnia may involve anxiety, sleep apnoea, medication, caffeine or an unsuitable sleep schedule. Melatonin does not necessarily address these causes.

Timing and dosage

The authorised EU claim for reducing the time needed to fall asleep applies to 1 mg consumed close to bedtime.

Timing varies according to the goal. Circadian-rhythm disorders may require administration earlier than standard bedtime use. A 2024 meta-analysis confirmed that both dose and timing influence the response, but its average results should not be treated as a universal personal protocol.

Jet lag

For jet lag, the EU-authorised claim applies to at least 0.5 mg taken close to bedtime on the first day of travel and for the following few days after arrival.

The timing should follow the destination time zone. Morning light, evening light management and gradual schedule adjustment are also important.

Safety

Short-term melatonin use appears safe for most adults, but long-term safety remains insufficiently established. Common adverse effects include daytime sleepiness, headache, dizziness and nausea.

Medical guidance is appropriate during pregnancy or breastfeeding, with epilepsy, anticoagulant use, serious medical conditions or concurrent sedative medication.

People who remain sleepy after taking melatonin should not drive or operate machinery.

Melatonin may not be sufficient when sleep difficulty is primarily related to stress or anxiety.

Conclusion

Melatonin is most useful for sleep timing, jet lag and selected circadian-rhythm problems. Its average effect on ordinary chronic insomnia is generally modest.

Correct timing and the lowest effective amount are more important than automatically choosing a high dose.

References

1. European Commission. Commission Regulation (EU) No 432/2012. Adopted May 16, 2012; consolidated through August 20, 2025.
2. National Center for Complementary and Integrative Health. Melatonin: What You Need to Know. Accessed August 2, 2026.
3. Maruani J et al. Melatonin and Ramelteon for Insomnia Disorder in Adults. Published online July 11, 2023; issue date December 2023.
4. Cruz-Sanabria F et al. Optimizing the Time and Dose of Melatonin as a Sleep-Promoting Drug. Published August 2024.
5. Besag FMC et al. Adverse Events Associated With Melatonin for Sleep Disorders. Published December 2019.
6. Herxheimer A, Petrie KJ. Melatonin for the Prevention and Treatment of Jet Lag. Published 2002.