The practical answer

Under regulation 2 of the Human Medicines Regulations 2012, a product is a medicine if it is presented as treating or preventing disease, or may be administered to people to modify physiological function. MHRA decides case by case and looks at all claims, including websites and social media, so a "research use" label does not settle status. Selling or supplying an unauthorised medicinal product is prohibited by regulation 46. [1] [2] [3]

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The question UK buyers ask

UK laboratories buying research peptides from EU or US suppliers want to know whether the product is "legal" and what to keep on file. UK law does not answer that by product name. It asks whether a given product, as presented and as it functions, is a medicinal product. This guide sets out the official tests and the records that show how your lab bought and used the material.

This is not legal advice and gives no guidance on any human or animal use.

The two-limb definition

MHRA Guidance Note 8 quotes regulation 2: a medicinal product is any substance or combination of substances presented as having properties for treating or preventing disease in human beings (the presentational limb), or which may be used in or administered to human beings with a view to restoring, correcting or modifying physiological functions by a pharmacological, immunological or metabolic action, or to making a medical diagnosis (the functional limb). Falling under either limb is enough. [1]

On function, GN8 cites European Court of Justice judgments requiring a case-by-case assessment of composition, pharmacological properties, manner of use, extent of distribution, consumer familiarity and risks. [1] GN8 also says MHRA classifies finished products, not individual substances, and that products containing substances primarily developed for non-medicinal purposes, such as industrial or agricultural use, with no valid use in clinical practice are unlikely to fall within the function limb. [1]

Presentation: why the website matters

GN8 says MHRA considers all claims, explicit and implicit, including those on websites, helplines, testimonials, linked publications and social media, and that product names can be implicit claims. Forms of marketing it lists as suggesting a medicine include references to medical conditions, comparison with licensed medicines, references to interference with physiological function, and references to medical or clinical research and testing. [1]

MHRA's borderline-products page adds that it considers labels, websites, social media and customer reviews, and the primary intended purpose or the way consumers would use the product. [2] For a buyer, that means the supplier's whole presentation is evidence, not only the "research use only" line on the label.

What MHRA looks atSourceWhat a lab buyer can record
Claims on labels, websites, social media, reviewsGN8 and borderline page [1] [2]Dated screenshots of the product page as ordered
Pharmacological properties and manner of useGN8 functional limb [1]Your documented laboratory purpose
References to clinical research or conditionsGN8 list of medicinal claims [1]Note any such statements on the supplier site
Primary intended purposeBorderline page [2]Purchase order wording and project reference

Selling, supplying and importing

Regulation 46 provides that a person may not sell or supply, or offer to sell or supply, an unauthorised medicinal product. [3] Regulation 17 requires a manufacturer's licence to import a medicinal product into Great Britain from a country other than Northern Ireland or an approved country for import, or into Northern Ireland from a country other than an EEA State. [4]

GOV.UK guidance on importing human medicines says importers need a wholesale dealer's licence, a manufacturer's licence or a marketing authorisation depending on route, that unlicensed medicines require a specials or wholesale licence and prior notification to MHRA, and that products containing controlled substances require contact with the Home Office. [5] That page does not address laboratory reagents bought for research, and we found no MHRA page that does. If your material could be a medicinal product, ask MHRA or a regulatory adviser rather than relying on a supplier's description.

How MHRA acts on a borderline product

GN8 describes a statutory procedure under Part 9 of the Regulations: MHRA may ask the manufacturer, importer or distributor for composition, presentation and purpose, issue a provisional determination that the company can contest before a Review Panel, and then a final determination. It can then issue a notice under regulation 163 formally requiring the company to stop marketing the product, and breach of such a notice can be a criminal offence. [1] The borderline page says most cases end in voluntary compliance, that investigations may be escalated towards prosecution, and that non-UK companies selling direct to UK consumers may fall outside MHRA jurisdiction. [2]

MHRA offers a borderline advice route for products a company plans to sell in the UK, with a limit of normally four enquiries from the same person, and GN8 should be read first. [2]

What a UK lab should keep on file

Keep a short regulatory note for each supplier and product: the supplier's legal entity and country, dated captures of the product page and terms as ordered, the purchase order describing the laboratory purpose, the lot certificate and safety data sheet, who imported the goods and on what basis, and any regulator advice obtained. If the supplier's site makes disease or clinical claims alongside a research-only disclaimer, record both; GN8 says such claims are what MHRA examines. [1]

A fictional entry: "Supplier X (Netherlands). Product page captured 29 Oct 2026: research-only statement; no disease claims seen. PO states in-vitro assay calibration. Importer: supplier ships DDP; licence basis not stated, asked in writing."

Questions before you decide

Does "not for human consumption" make a peptide lawful to sell in the UK?

Not by itself. MHRA decides status case by case from all claims and the product's function, including websites and social media.

Is an MHRA opinion that a product is not a medicine an approval?

No. GN8 says a non-medicinal decision does not authorise placing a product on the market and does not mean MHRA has approved or endorsed it.

Check the underlying evidence

Sources & review dates

Sources are documentary evidence. They do not establish firsthand testing of a listed supplier.

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