Circadian hormone · Fact sheet
Melatonin
Melatonin is a hormone involved in sleep timing. Evidence is more useful for certain circadian-rhythm problems than for broad claims about treating chronic insomnia, and long-term safety remains less certain.
What is Melatonin?
The body produces melatonin in response to darkness as part of its internal timing system. Melatonin supplements are regulated differently from prescription medicines in the United States.
Benefits people look for
Falling asleep earlier, reducing jet lag, and improving sleep quality are common goals. Sleep timing, sleep duration, and next-day function are distinct outcomes.
What the evidence supports
- The delayed-sleep trial found earlier sleep onset and improvement in some sleep-related impairment measures.
- It does not establish a universal remedy for chronic insomnia or prove long-term safety.
All research areas
- Delayed sleep-wake phase disorder
- Jet lag
- Sleep initiation
Anecdotal reports & lived experiences
Reports describe what someone noticed. They cannot establish cause, typical results, or how often a side effect happens.
Staying asleep, but with disturbing dreams
A person reported that melatonin gummies helped them stay asleep but were repeatedly followed by unusually vivid and sometimes frightening dreams.
This is a selected account with limited formulation and health-history detail. It does not establish how common nightmares are or whether melatonin caused them.
Read the sleep-and-dream account ↗Side effects & risks
- Headache, dizziness, nausea, and daytime sleepiness are reported.
- An analysis of commercial supplements found substantial variation from labeled melatonin content and serotonin in some products.
- Long-term effects, particularly in children, are less well understood.
This is a summary of the cited evidence, not a complete product label. A lack of human safety data does not establish safety.
Clinical research: how strong is it?
Moderate human evidenceIn a four-week trial, 116 people with verified delayed sleep-wake phase disorder were randomized to melatonin or placebo alongside behavioral scheduling. Results in that selected group do not apply to every sleep complaint.
Selected research to read
116 randomized participants; four-week follow-up and a selected circadian population.
Product-analysis study showing label variability; not every current product was tested.
FDA approval & research status
Melatonin has no FDA-approved drug indication for the wellness uses discussed here. Supplement availability is not premarket FDA approval of effectiveness or safety.
No FDA-approved use is documented in the records summarized on this page.
Supplement research is not FDA drug approval
Melatonin has no FDA-approved drug indication for the wellness uses discussed here. Supplement availability is not premarket FDA approval of effectiveness or safety.
This summarizes the cited product or research record. Trial phases do not establish successful completion of earlier stages, and a stopped program is not ongoing development. Approval applies only to the labeled product, use and population.
What we still don’t know
- Long-term safety and developmental effects
- Which sleep problems benefit most
- Reliability of individual supplement contents
The takeaway
It does not establish a universal remedy for chronic insomnia or prove long-term safety.
Sources & further reading
Medical evidence and regulatory sources are listed here. Personal reports are linked separately in the experiences section.
- 1nihNCCIH: melatonin evidence and safety
Condition-specific evidence, short-term adverse effects, and long-term uncertainties.
- 2pubmedMelatonin plus behavioral scheduling for delayed sleep
116 randomized participants; four-week follow-up and a selected circadian population.
- 3pubmedMelatonin supplement content and serotonin testing
Product-analysis study showing label variability; not every current product was tested.