Melatonin in the UK: Prescription-Only Status, Brands and Import Rules

Quick reference

• Drug class: Hormone / sleep aid
• Controlled substance: No, not scheduled under the Misuse of Drugs Act 1971 or any UK controlled-substance schedule
• Prescription required: Yes, melatonin is a prescription-only medicine in the UK. Circadin (2 mg prolonged-release) and Slenyto (1 mg and 5 mg, paediatric) are the licensed products and both are POM.
• Available locally: On prescription only: Circadin and Slenyto are licensed and dispensed by UK pharmacies. No melatonin product is authorised for over-the-counter sale, and supplements sold online or in health shops are not licensed medicines.
• Storage: Room temperature, below 25°C, away from direct light and moisture
• Max supply to carry: Up to 3 months' supply carried with you. More than that, or medicine posted to you, can be taken away at the border.
• Key document: Doctor's letter on clinic letterhead for quantities that might raise customs questions; original pharmacy packaging with label
• Emergency alternative: There is no legal over-the-counter melatonin in the UK. Book a private GP or online doctor consultation for a private prescription, or call NHS 111 for urgent advice.

Can you bring melatonin into the UK?

Yes. Melatonin is legal in the UK but it is a prescription-only medicine^[3], so you cannot buy it over the counter, including as a supplement. It is not a controlled drug, so you can bring your own supply with you, up to 3 months' worth^[6], in its original packaging; medicine posted to you, or more than 3 months' supply, can be taken away at the border. Once you are in the UK, the only legal way to get more is a doctor's prescription dispensed by a pharmacy.

This guide covers what documentation to carry, how much to bring, local availability of Circadin and Slenyto, and what to do if your supply runs out or is lost.

Medical disclaimer: This guide is for informational purposes only and does not constitute medical advice. Always consult your prescribing doctor before travelling with medication, particularly regarding supply quantities, storage requirements, and import documentation.

Documentation for travelling to the UK with melatonin

Melatonin is not a controlled substance under the Misuse of Drugs Act 1971, so no import permit is required to bring it into the UK^[2] for personal use. A doctor's letter on clinic letterhead is still recommended for quantities above a few weeks' supply, particularly if you carry Circadin or Slenyto in their prescription packaging.

Because the UK's official language is English, no translation is required. Notarisation and apostille are not needed for personal medication documentation at UK borders.

How much melatonin to bring

GOV.UK limits the medicine you carry into the UK to 3 months' supply^[6]. If you bring more than that, or have medicine posted to you, it can be taken away. If you do not live in the UK, carry a letter from your prescriber confirming the medicine was prescribed for you, with your travel dates and their signature.

Bring enough for your full trip plus a 10-day buffer in case of delays or lost luggage, keeping the total within 3 months' supply. If you take Circadin or Slenyto and your supply runs out, obtaining the same formulation locally requires a UK prescription, so a buffer is practical insurance.

Packing and storing melatonin for travel

Melatonin tablets and capsules should be stored below 25°C, away from moisture and direct light^[4], according to the Circadin summary of product characteristics published by the MHRA. Standard room-temperature storage is sufficient for transit; no cooling wallet or insulated bag is required. Keep tablets in the original blister pack to protect them from humidity during travel.

Airport security with melatonin

Melatonin tablets are solid oral medications and are not subject to the 100 ml liquid restriction at airport security. The UK Civil Aviation Authority and airport security rules^[5] allow passengers to carry solid medications in hand luggage without quantity limits, provided the medication is for personal use. You do not need to declare melatonin proactively at the security checkpoint.

Keep the medication in its original packaging with the pharmacy label visible. If a security officer asks you to remove it from your bag, present the packaging and your doctor's letter. There are no sharps or liquid concerns for standard melatonin tablet formulations.

Customs and medication import rules for the UK

Melatonin is not listed as a controlled or prohibited substance under UK Border Force guidance. UK Border Force rules on bringing medicines into Great Britain^[6] require that prescription medicines are carried in their original packaging with a pharmacist's label and, where possible, accompanied by a prescription or letter from a prescribing doctor.

No import permit or prior notification to UK authorities is needed for melatonin, but the 3-month limit on medicine carried in person still applies. If you are carrying Circadin or Slenyto in prescription packaging, carrying your original prescription alongside is straightforward evidence of personal use.

Melatonin availability in the UK

Melatonin cannot be bought without a prescription anywhere in the UK. The MHRA classes every melatonin-containing product as a medicine^[3], so supplements, gummies and sprays sold online or on marketplaces are unlicensed and not legally supplied. High-street pharmacies, health shops, supermarkets and airport shops do not stock it.

Licensed products include Circadin 2 mg prolonged-release for adults aged 55 and over^[7] and Slenyto for children. Other licensed melatonin products cover jet lag in adults and sleep problems in children with ADHD. All of them are prescription-only^[11].

If you take Circadin or Slenyto and need an in-country refill, a UK private prescription is required. The NHS does not provide prescriptions to visitors without registration with a GP practice, which is not practical for short stays.

Finding a doctor who can prescribe melatonin in the UK

Private GP clinics operate throughout the UK and can issue a private prescription for Circadin, often on the same day. Fees vary by clinic and city, so check the price when you book. The General Medical Council register^[8] allows you to verify that any prescribing doctor is GMC-registered before your appointment.

Several UK online doctor services offer video consultations with GMC-registered doctors who can issue private prescriptions. Check the doctor on the GMC register and confirm the service is registered with the Care Quality Commission.

Storing melatonin while in the UK

The UK's temperate climate rarely presents storage challenges. Circadin should be stored below 25°C in a dry place^[4], which standard hotel room temperature satisfies year-round. Summer temperatures in London and other English cities occasionally reach 30°C; keep medication away from direct sunlight and out of a car glove box on warm days.

Refrigeration is not required for melatonin. In the rare event of a prolonged heatwave, store your supply in the coolest part of your accommodation and away from windows.

What to do if something goes wrong with your melatonin in the UK

If your Circadin or Slenyto is lost or stolen, contact your travel insurer immediately and obtain a police reference number if theft is suspected. Report the loss to the nearest pharmacy to begin the process of obtaining a replacement prescription from a UK private GP.

If you run out, there is no over-the-counter substitute in the UK. Visit a private GP clinic or use an online doctor service for a same-day private prescription, which a UK pharmacy can dispense. Bring your original packaging or prescription to show your usual dose, and call NHS 111 if you need urgent advice. See our healthcare guide for the UK for more information on provider options.

The UK emergency number is 999 for life-threatening situations and 111 for non-emergency medical advice available 24 hours a day. NHS 111 can direct you to the nearest out-of-hours GP or urgent treatment centre^[9] if you need a same-day prescription.

Frequently asked questions

Sources

1. [1] MHRA — Circadin 2 mg prolonged-release tablets: Summary of Product Characteristics
2. [2] UK Home Office — Misuse of Drugs Act 1971: Schedules of Controlled Drugs
3. [3] MHRA: melatonin is a prescription-only medicine (press release, August 2025)
4. [4] electronic Medicines Compendium (eMC) — Circadin 2 mg: Storage conditions
5. [5] UK Civil Aviation Authority — Taking medicines on an aircraft
6. [6] GOV.UK: Take medicine in or out of the UK
7. [7] MHRA — Circadin: prescription-only medicine classification
8. [8] General Medical Council — Register of licensed medical practitioners
9. [9] NHS: When to use NHS 111 online or call 111
10. [10] Slenyto 1 mg prolonged-release tablets — Summary of Product Characteristics, emc
11. [11] NHS: About melatonin

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