Sleep aid / hormone · ATC N05CH01
Melatonin
The international (INN) name. Pharmacists everywhere recognize it, even when the local brand differs (e.g. Circadin, Sold as a supplement, Melatobel).
Sold for: jet lag and sleep.
Regulated as a medicine, not a supplement, even at low doses. Bringing your own is often more reliable than buying it locally.
No prescription needed for adults (18 and over); for anyone under 18 it needs a prescription.
Under 2 mg per dose it is sold without a prescription as a food supplement; 2 mg and above is a prescription medicine.
Some products are registered as prescription-only.
Prescription-only, and licensed as a children’s medicine. Melatonin is not sold as a supplement in Japan, so bring your own supply.
Possession without a prescription isn’t a criminal offence, but importing/distributing without approval can carry fines up to S$10,000 and possible imprisonment.
Sold as a supplement in some pharmacies, but the local rules are not known. They may follow France’s pharmacy rules.
Sold OTC as a food supplement up to roughly 2mg/day (recent guidance pushes suppliers toward ≤1mg); products at 2–3mg are regulated as INFARMED prescription medicines.