Melatonin in Japan: the OTC search, supplements and the rules

Its official name in Japan

The official English and Japanese names come from the JAN database and the Japanese Pharmacopoeia.

Melatonin and Japanese OTC medicine

On 3 October 2026, PMDA's search of OTC package inserts returned no products containing melatonin.

Japan's health ministry: melatonin is a hormone secreted by the pineal gland, and in Japan it is an ingredient used only as a medicine.

Its list of ingredients used only as medicines (updated 5 August 2026) names melatonin (松果体ホルモン, pineal hormone).

Bringing it into Japan

Japan's health ministry lists melatonin among ingredients used only as medicines. Products sold abroad as food or supplements can count as medicine in Japan if they contain a medicinal ingredient. For medicine you bring for your own use, the ministry's limits are up to 1 month's supply of poisons, powerful drugs and prescription drugs, and up to 2 months' supply of other medicine.

• Bringing vitamins and supplements into Japan
• How much medicine you can bring into Japan

Taking it home

What the official customs pages say about melatonin. Check them before you fly.

• South Korea: The Korea Customs Service's press release of 17 July 2025 gives, as examples, Japanese painkillers containing the psychotropic drug allylisopropylacetylurea, US cold medicines containing dextromethorphan and supplements containing melatonin, and says these medicines and foods are banned from being brought into Korea.

• Taking Japanese medicine home: the limits in South Korea, Taiwan, mainland China and Hong Kong

Source: Korea Customs Service — Narcotics and psychotropic ingredients (마약류 성분 목록) · Korea Customs Service — Press release, 17 July 2025 (보도자료) · Korea Customs Service — Check the ingredients of medicine you bring in (의약품 성분 확인)

Related items

• Buying medicine in Japan
• Taking Japanese medicine home