Defining “medicines”

The Human Medicines Regulations 2012 define medicines as:

Any substance or combination of substances presented any one of the following:

• having properties for treating or preventing disease
• used for restoring, correcting or modifying a physiological, metabolic or immunological function
• administered to make a medical diagnosis

Medicines include licensed medicines (including medical gases and radiopharmaceuticals), unlicensed medicines, herbal medicines and advanced therapy medicinal products (ATMPs).

For more information see the MHRA’s guide to what is a medicinal product.

Medicinal products, whether licensed or unlicensed, must be produced in accordance with Good Manufacturing Practice (GMP).

Licensed medicines

Medical treatment should always use licensed medicines wherever possible, and this is the case for most patients.

A medicinal product can generally only be placed on the market when it has been assessed by the Medicines and Healthcare products Regulatory Agency (MHRA) to meet the quality, safety and efficacy standards for its intended use and has been granted a Marketing Authorisation (MA) in the UK.

For more details on the licensing of medicines in the UK, see the MHRA page UK-wide licensing for human medicines.

Labelling and impact of Windsor Agreement

The Windsor Agreement, in effect from 1 January 2025, means that all licensed medicines in the UK are approved and authorised by the MHRA through UK-wide Marketing Authorisations.

The Marketing Authorisation number on the outer packaging will take one of two different formats, depending on when the medicine was authorised:

• medicines with a PLGB prefix, for example PLGB/12345/12340, were authorised for the Great Britain (GB) market before 1 January 2025 but are now valid for the whole of the UK
• medicines with a PL prefix, for example PL/12345/12340 have UK-wide Marketing Authorisations.

From 1 January 2025, all UK-licensed medicines must bear ‘UK only’ on the outer packaging.

There may be medicines without ‘UK only’ available on the UK market for a period until their expiry date. If obtained from bona fide sources, these medicines can continue to be used until their expiry date.

For more information, see the MHRA page Labelling and packaging of human medicines following the Windsor Agreement.

Parallel imports

Parallel imports (PIs) are licensed medicines in the UK. The MHRA parallel import licensing scheme lets a medicine authorised in an EEA Member State be marketed in the UK as long as the imported product has no therapeutic difference from the equivalent UK-licensed product. Lists of medicines granted parallel import licences are published monthly on the MHRA’s website.

PIs do not have packaging and labelling identical to the UK product. They may be simply EU packs over-labelled for the UK market or may be entirely re-boxed and re-labelled so that none of the original outer packaging and labelling remains. Sometimes products are a combination of re-boxed and over-labelled. However, the primary packaging (e.g. blister strip) must remain intact, to help ensure the integrity and stability of the product.

They do not have a UK Summary of Product Characteristics (SmPC), however there will be a PIL in the box containing information for healthcare professionals where relevant. You may also refer to the SmPC for the for the equivalent UK product, acknowledging there may be minor differences in sections 5 & 6.

Since 1 January 2025, all PIs are authorised across the whole of the UK and will have a valid PLPI licence from the MHRA. All PLPI licenses will continue to have the prefix ‘PLPI’, and the licence number will not change. PLPIs with a current territorial limitation of GB will be converted to UK-wide authorisations automatically. PIs released to the UK market after 1 January 2025 will contain a prefix ‘PL’ on all labels and leaflets in the format PL/12345/12340.

As for all UK-licensed medicines PIs must bear ‘UK only’ on the outer packaging, although there may be medicines without ‘UK only’ available on the UK market for a period until their expiry date. If obtained from bona fide sources, these medicines can continue to be used until their expiry date.

For more information about parallel imports, see the MHRA’s pages on UK parallel import licences following Windsor Framework Agreement and applying for a parallel import licence.

Unlicensed medicines

Any medicine that meets the definition of a medicine but does not have a Marketing Authorisation valid in the UK is classified in the UK as an unlicensed medicine.

Unlicensed medicines may only be prepared and supplied under an exemption from the Human Medicines Regulations 2012 (SI 2012/1916).

MHRA Guidance Note 14 details the exemption provided by the medicines legislation to allow supply (often referred to as placing on the market) of an unlicensed medicinal product to meet the special clinical need of an individual patient.

Another exemption (Section 10 exemption from the Medicines Act 1968) permits the preparation and supply of unlicensed medicines in a registered pharmacy, a hospital or a health centre by or under the supervision of a pharmacist in accordance with a prescription given by an appropriate practitioner.

Understanding unlicensed medicines provides additional information about types of unlicensed medicines.

Borderline substances

Some products may be hard to distinguish from medicines, such as cosmetics, food supplements or medical devices.

In certain conditions, some foods (and toilet preparations) are regarded as medicines for the management of certain conditions, The MHRA Advisory Committee of Borderline Substances (ACBS) advises on the circumstances under which such substances may be regarded as medicines.

The MHRA’s guide How to tell if your product is a medicine provides more information about borderline products.

Medical devices

Medical devices are regulated separately to medicines. The MHRA determines whether or not a product is a medical device. A medical device is one where the principal intended action must primarily be fulfilled by physical or mechanical means. It may not act principally by pharmacological, metabolic or immunological means, although ancillary action is permitted.

Like medicines, medical devices are marketed for a specific purpose and their use for any other purpose is off-label.

The risks of using a medical device containing a medicine, off-label for a medicinal purpose, should be carefully evaluated as part of the treatment decision. Examples of off-label use of medical devices include:

• lidocaine in a lubricating gel used as an anaesthetic agent
• triamcinolone intraocular opacifying suspension used for treatment of macular oedema
• methylthioninium chloride dye used for treatment of methaemaglobinaemia

A medical device must bear a UKCA mark to be legally marketed in GB. Some medical devices will still bear a CE mark on the packaging until June 2028. More information about medical devices can be found on the MHRA’s web pages.

Nutritional products

A food supplement is defined as “a concentrated source of a vitamin, mineral or other substance with a nutritional or physiological effect, alone, or in combination, sold in dose form”. Further information about food supplements can be found on the GOV.UK website.

Foods for special medical purposes (FSMP) are nutrition products for the dietary management of a specific disease, disorder or medical condition. These are specialist foods intended for the exclusive or partial feeding of people whose dietary management cannot be achieved by modification of the normal diet alone.

Food supplements and FSMPs are not medicines. The MHRA decides whether the claims made or active substance present, mean that a product is a medicine.

Food supplements are made to different quality standards to medicines. Nutrition law does not require manufacture to be compliant with Good Manufacturing Practice (GMP). However, nutrition products must still meet their description and must be safe.

The competent authorities in GB are The Department of Health and Social Care (DHSC), Food Standards Scotland (FSS) and the Welsh Government.

Safety issues should be reported to the Food standards agency.

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