Melatonin
Strong evidence for circadian rhythm disruption (jet lag, shift work, delayed sleep phase); more modest effect size for chronic general insomnia, where behavioral treatments (CBT-I) have stronger evidence.
1. Overview
What it is
A hormone naturally produced by the pineal gland in response to darkness, signaling the body's internal clock that it is nighttime.
How it works
Binds melatonin receptors (MT1/MT2) in the brain's suprachiasmatic nucleus, helping to shift and reinforce circadian sleep timing rather than acting as a direct sedative.
Who should take it
People with jet lag, shift workers, those with delayed sleep phase syndrome, and some older adults with lower natural melatonin production.
Who should avoid it
People on anticoagulants, immunosuppressants, or diabetes medications should consult a physician; not recommended for long-term unsupervised use in children.
Evidence summary
Cochrane and other systematic reviews show consistent benefit for circadian-rhythm-related sleep problems; effect on falling asleep faster in general insomnia is present but modest (roughly 7-12 minutes faster sleep onset on average).
Scientific mechanism
Signals circadian phase to the suprachiasmatic nucleus via MT1/MT2 receptor binding, shifting the timing of the sleep-wake cycle rather than directly sedating.
2. Scientific Evidence Rating
Strong Evidence — based on high-quality human evidence including systematic reviews, meta-analyses, randomized controlled trials, and major clinical guidance where available.
Ratings reflect the overall quality and consistency of human evidence, not marketing claims. Where evidence is mixed, this is stated explicitly rather than rounded up.
3. Safety Rating
4. Is It Worth Taking?
Strong evidence for circadian rhythm disruption (jet lag, shift work, delayed sleep phase); more modest effect size for chronic general insomnia, where behavioral treatments (CBT-I) have stronger evidence.
5. Benefits
Each benefit is tagged with its own evidence strength — not every claim about a supplement is equally well supported.
- ★★★★☆ Reduces jet lag symptoms and speeds circadian adjustment
- ★★★☆☆ Modestly reduces time to fall asleep in general insomnia
- ★★★★☆ Helps regulate sleep timing in shift workers and delayed sleep phase disorder
- ★★☆☆☆ Effect on total sleep duration/quality is smaller than on sleep onset
6. Risks
Side effects
Grogginess/morning drowsiness, headache, dizziness, vivid dreams; generally mild.
Drug interactions
Can potentiate sedatives and blood thinners; may affect blood sugar control in diabetics; can interact with immunosuppressant drugs.
Who should avoid it / use caution
7. Recommended Dosage
8. Best Time To Take
- 30–60 minutes before desired bedtime
- For jet lag: near the target bedtime of the new time zone
9. Food Sources
- Tart cherries
- Walnuts
- Small amounts in some grains — dietary contribution to sleep is minimal compared to supplemental doses
10. Deficiency Symptoms
Supplementation is most clearly evidence-based when it corrects an actual shortfall like the ones below — not as a routine addition for people who are already sufficient.
- Not a classic dietary deficiency — natural production declines with age and can be disrupted by irregular light exposure, shift work, and screen use at night
FAQ
Is melatonin addictive?
No evidence of physical dependence or withdrawal has been established, unlike some prescription sleep aids.
Why do some people wake up groggy?
This is usually due to too high a dose or taking it too late relative to the desired wake time — lower doses (0.5-1mg) taken earlier often work better than very high doses.
11. Scientific References
Ratings and content on this page are based on the consensus of the following types of high-quality sources. This is educational information, not individual medical advice.
Key Research Papers
- Cochrane review: melatonin for prevention/treatment of jet lag (PMC)
- Meta-analysis: melatonin for primary sleep disorders (PMC)
General Reference Organizations
⚕️ This page does not diagnose, treat, cure, or prevent any disease. Melatonin is not a substitute for a varied diet or professional medical care. Always consult a qualified healthcare provider before starting any new supplement, especially if pregnant, breastfeeding, managing a health condition, or taking medication.