What it’s for
- Jet lag
- Selected circadian sleep-timing disorders
Timing, formulation, age and the sleep problem matter. It is not a general-purpose substitute for evaluating persistent insomnia.
A hormone involved in circadian timing, also taken as a supplement or medicine.
Purpose, evidence and practical considerations.
Timing, formulation, age and the sleep problem matter. It is not a general-purpose substitute for evaluating persistent insomnia.
Evidence supports some circadian uses, while chronic-insomnia guidelines find insufficient evidence to recommend routine melatonin treatment. Long-term safety and supplement consistency remain concerns.
Confidence: strong
Possible effects include sleepiness, headache, dizziness, vivid dreams and impaired next-day alertness. Avoid driving after use. Pregnancy, childhood use, seizure disorders and interactions with anticoagulants, sedatives, immunosuppressants or glucose and blood-pressure medicines warrant professional advice. US supplements can be substantially mislabelled, so independently verified products are preferable.
Melatonin is an endogenous circadian hormone. Exogenous melatonin can signal biological night and shift circadian phase when timed correctly; it also has a modest direct sleep-promoting effect. Timing, immediate- versus prolonged-release form and indication matter more than treating every dose as interchangeable.
Regulatory status: medication in the UK and much of the EU; dietary supplement in the United States
How people use it, with their schedules, context and original sources.
300 mcg · nightly · at night
0.21 mg
3 mg · when needed; cycles off · night
night terrors
Amount and timing patterns reported in public protocols; these are observations, not instructions. Private and hidden usage is excluded.
These share a protocol with this intervention. This does not establish that they work together or are suitable alternatives.