Melatonin: sleep benefits, limits and precautions

Melatonin is a hormone involved in synchronising the sleep–wake rhythm. A supplement may help in some settings, especially jet lag, but it is not a universal sleeping pill or an automatic answer to persistent insomnia.

Evidence suggests possible value for some circadian-rhythm problems and jet lag. For chronic insomnia, effects remain modest or uncertain and vary by formulation and person. Persistent poor sleep or daytime impairment deserves assessment rather than prolonged self-medication.

Melatonin acts as a biological signal linked to the body clock. Taking it at the wrong time may be ineffective or shift the rhythm further. Follow the product instructions and ask a professional for advice, especially when the goal is not occasional jet lag. Do not drive if drowsiness persists.

Drowsiness, headache, dizziness or unusual dreams may occur. Use extra caution during pregnancy or breastfeeding, in children and adolescents, and with chronic disease. Supplements are not automatically equivalent to medicines assessed in medical care.

Melatonin may interact with sedatives, some medicines affecting blood clotting, anti-seizure medicines, diabetes or blood-pressure treatments, and other products. Ask a doctor or pharmacist before use if you take regular medication. Do not replace or stop prescribed treatment.

Seek advice if sleep problems persist, cause marked daytime sleepiness, involve loud snoring with breathing pauses, severely affect mood, or lead to increasing reliance on sleep products. A regular schedule, morning light and behavioural treatment may be more appropriate than a supplement.