Is melatonin a food supplement or a medicine in the UK? It is a medicine. The NHS states that melatonin is a prescription-only medicine and that melatonin supplements sold in health-food shops abroad are not authorised for sale in the UK. The Great Britain nutrition and health claims register also records two authorised food claims for melatonin.
That second sentence is the part nobody on the first page of results explains, and it is why this desk read both documents on 11 September 2026 rather than one. A substance can sit in the medicines regime and have a permitted claim wording sitting in the food register at the same time. Understanding how that is possible is the whole answer to the question.
Why is melatonin a medicine and not a food supplement in the UK?
Start with the NHS page on melatonin, which is written for patients and is unusually plain on the point. Under the question “Can I buy melatonin supplements at a health food shop?” it says that in some countries melatonin is sold in health-food shops or online as a complementary medicine, in capsules, tablets or a liquid, but that “these supplements are not authorised for sale in the UK and it’s a prescription-only medicine.” The companion page says melatonin “is available on prescription only” and lists the brand names Circadin, Adaflex, Ceyesto, Slenyto and Syncrodin.
The reference product is Circadin 2 mg prolonged-release tablets. Its summary of product characteristics, published on the electronic medicines compendium, indicates it as monotherapy for the short-term treatment of primary insomnia characterised by poor quality of sleep in patients aged 55 or over, at 2 mg once daily, one to two hours before bedtime and after food, for up to thirteen weeks. The emc also lists Slenyto 1 mg and 5 mg prolonged-release tablets from Flynn Pharma; we did not read that product’s SmPC and make no claim about what it is indicated for.
Two housekeeping points about the NHS pages, because a reader who lands on them will notice. Both display “Page last reviewed: 13 February 2023” and “Next review due: 13 February 2026”, so on 11 September 2026 the stated review date has passed by seven months. That is a statement about what the page shows, not evidence that its content is wrong. And the NHS page attributes the prescription-only status to no document. For the mechanism behind it you have to go to the medicines regulator.
Who decides, and on what test?
The Medicines and Healthcare products Regulatory Agency publishes a guidance page, Borderline products: how to tell if your product is a medicine, last updated on 2 July 2026. It says the MHRA “determines whether a product falls within the definition of a medicinal product”, and it names food products, “including, in particular, food supplements”, among the borderline types it deals with.
The test is the definition in Regulation 2 of the Human Medicines Regulations 2012, which the page sets out in two limbs. A product is a medicinal product if it is presented as having properties for preventing or treating disease, or if it may be used by or administered to human beings “with a view to restoring, correcting or modifying a physiological function by exerting a pharmacological, immunological or metabolic action”. The second limb is the one that matters for a hormone. The page is careful to add that food supplements containing familiar substances such as vitamins, amino acids or minerals are generally subject to food law rather than medicines control “unless presented for medicinal uses”, and that the MHRA decides whether the claims made or the active substances present mean a product should be regarded as a medicinal product.
So the question of whether melatonin is a food supplement or a medicine is not answered by the food regulators at all. It is answered by the MHRA applying the medicines definition to the substance and its presentation. We covered the same borderline last month when the MHRA drew its microbiome line, and the logic here is the same one, pointing the other way.
What does the GB claims register say about melatonin?
This is the part of the answer the pharmacies and clinics on page one leave out. The Great Britain nutrition and health claims register is maintained by the Department of Health and Social Care and published on gov.uk, where the page states “Published 31 December 2020” and “Last updated 19 May 2026”. Its one-sentence rule is that “Only authorised claims in the Great Britain NHC register may be used in Great Britain.”
We downloaded the register spreadsheet dated 19 May 2026 from that page and searched it. Exactly three rows mention melatonin. This is what they record.
| Row | Claim wording (as recorded) | Conditions of use | Status in Great Britain |
|---|---|---|---|
| 1 | “Melatonin contributes to the alleviation of subjective feelings of jet lag” | Food must contain at least 0.5 mg of melatonin per quantified portion (printed as “0,5 mg”); consumer must be told the effect is obtained with a minimum intake of 0.5 mg close to bedtime on the first day of travel and the following few days after arrival | Authorised for use in Great Britain |
| 2 | “Melatonin contributes to the reduction of time taken to fall asleep” | Food must contain 1 mg of melatonin per quantified portion; consumer must be told the effect is obtained by consuming 1 mg close to bedtime | Authorised for use in Great Britain |
| 3 | Six wordings: helps to reduce jet lag effects; helps to reduce sleep onset latency; helps to regulate circadian rhythm; improves sleep-wake cycle; contributes to improve sleep quality; helps to fall asleep in a natural way | Not applicable. Reason given: the claimed effect “has not been substantiated” | Non-authorised |
Both authorised rows are Article 13(1) claims, cite EFSA opinions from 2010 and 2011, and give their legal basis as Commission Regulation (EU) 432/2012 of 16 May 2012. In other words they are the EU-era claim wordings carried into the GB register when it was created at the end of 2020. On the change log’s own account, the 19 May 2026 update to the register did not touch them: the change log for that date records the addition of one non-authorised claim for green kiwifruit powder and the publication of Excel versions alongside the OpenDocument files, and nothing else.
One incumbent on this query describes those claims as EU-only and attributes the UK position to an uncited “FSA position”. The register we read records them as authorised for use in Great Britain, and we cite nothing from the Food Standards Agency on this subject, because we read nothing from it; the melatonin decision belongs to the medicines regulator, not the food one.
How can both be true at once?
Because the two frameworks decide different things. The claims register decides what a food may say about an ingredient. It does not decide whether a given product is a food. Regulation 432/2012 authorised a wording for melatonin at 0.5 mg and 1 mg; that wording was inherited by Great Britain with the rest of the list, and it sits in the register whether or not any lawful product in Great Britain exists to carry it.
Whether a product containing melatonin is a food supplement or a medicine is a prior question, answered by the MHRA under the medicines definition. If the substance in the product, at the dose and in the presentation offered, meets that definition, it is a medicinal product and falls under medicines control, regardless of what the food register would let a label say. The NHS’s statement that the supplements sold abroad are not authorised for sale in the UK is a statement about that prior question.
The same shape appears wherever the site looks at this boundary. A traditional herbal registration proves something quite different from a food supplement’s paperwork, and permitted claims on the shelf have a way of trailing the marketing. Melatonin is the cleanest example we have found of the two registers pointing in different directions, with neither one wrong.
Why is melatonin banned in the UK?
It is not banned. The NHS melatonin pages, read on 11 September 2026, describe it as a prescription-only medicine, available from a doctor and sold under brand names including Circadin, Adaflex, Ceyesto, Slenyto and Syncrodin. What the NHS does say is that the melatonin supplements sold in health-food shops in some countries are not authorised for sale in the UK. A controlled medicine and a banned substance are different things.
Can I buy melatonin supplements at a health food shop?
Not according to the NHS. Its answer to exactly this question says that in some countries melatonin is sold in health-food shops or online as a complementary medicine, but that those supplements are not authorised for sale in the UK, where it is a prescription-only medicine. The NHS adds that ordering melatonin online is not recommended. The two authorised food claims in the GB register do not change that.
Can you buy melatonin over the counter in the UK?
No. The NHS states that melatonin is available on prescription only, and neither of the two NHS pages we read on 11 September 2026 describes a pharmacy or general-sale route. The reference product, Circadin 2 mg prolonged-release tablets, has a summary of product characteristics on the electronic medicines compendium, and the NHS is the page we rely on for the prescription-only status.
Who can be prescribed melatonin in the UK?
The NHS says melatonin is mainly used to treat short-term sleep problems in people aged 55 and over, and can sometimes be prescribed by specialists for longer-term sleep problems in some children and adults. The Circadin SmPC indicates 2 mg once daily for short-term primary insomnia in patients aged 55 or over, for up to thirteen weeks. For jet lag the NHS gives a usual dose of 3 mg, and says it may not be available on NHS prescription.
What this desk read, and what it did not
We read the two NHS melatonin pages, the gov.uk register page and its 19 May 2026 spreadsheet, the MHRA borderline guidance and the Circadin SmPC, all on 11 September 2026. We did not read the Slenyto SmPC, the legal-category line of the Circadin SmPC, or anything from the Food Standards Agency, and we make no statement about the EU-side status of the melatonin claims today. Any absence noted above is scoped to those documents.
The reading for a shopper is the usual one on this desk, with the sign reversed. A food supplement is regulated as food in Great Britain, not as a medicine, and is not there to diagnose, treat, cure or prevent anything; melatonin is the ingredient that fell on the other side of that line. Anyone who cannot sleep and wants melatonin wants a GP, not a label, and nothing here is medical advice.