Clinical trials for medicines: labelling
Source: gov.uk (2025-10-01)

Guidance on labelling for medicinal products used in clinical trials.

This guidance accompanies the Medicines for Human Use (Clinical Trials) Regulations 2004 (“the Clinical Trials Regulations”), as amended by the Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 (https://www.legislation.gov.uk/uksi/2004/1031/contents).

These amendments come into force on 28 April 2026.

Until this date, this guidance is in draft and should only be used to support sponsors in preparing for the implementation of the new regulations. Please see Clinical trials for medicines: apply for authorisation in the UK (https://www.gov.uk/guidance/clinical-trials-for-medicines-apply-for-authorisation-in-the-uk) and Clinical trials for medicines: manage your authorisation, report safety issues (https://www.gov.uk/guidance/clinical-trials-for-medicines-manage-your-authorisation-report-safety-issues) for the guidance that should be followed prior to 28 April 2026.

The Clinical Trials Regulations

The following guidance accompanies the Medicines for Human Use (Clinical Trials) Regulations 2004 (https://www.legislation.gov.uk/uksi/2004/1031/contents) (“the Clinical Trials Regulations”), as amended by the Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 (https://www.legislation.gov.uk/uksi/2025/538). These amendments come into force on 28 April 2026. For assistance in determining whether a clinical trial is within the scope of these Regulations, see the Is it a clinical trial of a medicinal product? (https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/949145/Algorithm_Clean__1_.pdf) algorithm.

Part 2 of Schedule 1 to the Clinical Trials Regulations requires that the investigator and sponsor (https://www.hra.nhs.uk/planning-and-improving-research/research-planning/roles-and-responsibilities/) (and any individual or organisation that the sponsor delegates trial-related activities to) have regard to all relevant guidance with respect to commencing and conducting a clinical trial. Investigators and sponsors must, therefore, ensure that they are fully aware of the information within this guidance and act accordingly to achieve and maintain regulatory compliance.

Labelling for investigational medicinal products (IMPs) used in clinical trials

IMPs that are not authorised in the UK, EU or an ICH region country

In most cases, if an IMP to be used in a clinical trial is not authorised (meaning that it does not have a UK marketing authorisation or Article 126a authorisation), it must be labelled with the following information, per regulation 46(1) of the Clinical Trials Regulations:
- the words “for clinical trial use only”
- a warning that the product must be stored out of the reach and sight of children (unless the product is to be exclusively administered in a hospital or health centre taking part in the clinical trial)
- information to identify the sponsor and contact persons involved in the clinical trial (e.g. the names and telephone numbers of the local investigator and sponsor or, if a telephone number cannot be provided, a clear strategy on how the person can be reached in a timely manner)
- information to allow identification of the clinical trial, for example the clinical trial reference code, the trial acronym (if unique), the protocol number, the IRAS number, etc.
- information linking the product to the participant, for example, the participant identification number or name
- the common name of the active substance (or the medical product code)
- the strength and pharmaceutical form
- the contents by weight, volume or number of doses
- the batch or code number
- instructions for use (which may be by reference to a patient information leaflet) or administration
- method or route of administration
- expiry date
- any special storage precautions
For support in determining how the required information should be included on the label, review the points in the table below.

Please also review the section of this guidance on trials in which blinding occurs (https://www.gov.uk/guidance/clinical-trials-for-medicines-labelling#labelling-imps-in-trials-where-blinding-occurs).

The exceptions to the requirement for an IMP that is not an authorised product to be labelled in accordance with regulation 46(1) of the Clinical Trials Regulations are:
- for IMPs to be exclusively administered in a hospital or health centre taking part in the clinical trial, the warning that the product must be stored out of the reach and sight of children may be included but is not mandatory
- for certain IMPs that are unauthorised in the UK but have an EU or ICH region authorisation, it may be acceptable for the labelling to contain less information. Further detail can be found in the guidance on IMPs that are not authorised in the UK but are authorised in the EU or an ICH region (https://www.gov.uk/guidance/clinical-trials-for-medicines-labelling#imps-that-are-not-authorised-in-the-uk-but-are-authorised-in-the-eu-or-an-ich-region)
IMPs that are authorised in the UK

If an IMP to be used in a clinical trial has a UK marketing authorisation or Article 126a authorisation, is not modified, and is used within the terms of that authorisation it must be labelled either:
- with the same information as unauthorised IMPs (i.e. in accordance with regulation 46(1) of the Clinical Trials Regulations)
in accordance with the existing UK requirements for prescribed medicines dispensed by pharmacies set out in Part 13 of the Human Medicines Regulations 2012 (https://www.legislation.gov.uk/uksi/2012/1916/contents/made). In addition, the label should, where possible, include either on the primary container or outer pack:
- the words “for clinical trial use only” or equivalent wording (note that reference to a “clinical study” rather than a clinical trial would not be considered equivalent)
- information to allow identification of the clinical trial, for example, the clinical trial reference code, the trial acronym (if unique), the protocol number, the IRAS number, etc. (see guidance in previous section)
- information to identify the sponsor and contact persons involved in the clinical trial (e.g. the names and telephone numbers of the local investigator and sponsor or, if a telephone number cannot be provided, a clear strategy on how the person can be reached in a timely manner)
Please note that it is acceptable to include cautionary and advisory labels recommended by the British National Formulary (BNF) on packaging, if the text of these labels is not already included in the pharmacy labelling. This additional labelling does not need to be submitted to the licensing authority as part of the application for clinical trial approval (https://www.gov.uk/guidance/clinical-trials-for-medicines-apply-for-approval-in-the-uk#applying-for-approval-for-a-clinical-trial).

However, where the IMP to be used in the trial is authorised in the UK and is either exclusively administered in a hospital or health centre taking part in the clinical trial or is a radiopharmaceutical used for diagnostic purposes, it can instead be labelled with at least the following information per regulation 46(3) and 46(4) of the Clinical Trials Regulations:
- the words “for clinical trial use only”, or equivalent wording (note that reference to a “clinical study” rather than a clinical trial would not be considered equivalent)
- information to allow identification of the clinical trial, for example, the clinical trial reference code or acronym (see guidance in previous section)
- information linking the product to the participant, for example, the participant identification number or participant name (see guidance in previous section)
- the common name of the active substance (or the medical product code)
- the strength and pharmaceutical form
- the contents by weight, by volume or by number of doses
- the batch or code number
- instructions for use or administration (which may be by reference to a patient information leaflet, if the patient is intended to take the product themselves)
- method or route of administration
- expiry date (see guidance in previous section)
- any special storage precautions
For support in determining how the required information should be included on the label, review the points in the table in the previous section.

Please also review the section of this guidance on trials in which blinding occurs (https://www.gov.uk/guidance/clinical-trials-for-medicines-labelling#labelling-imps-in-trials-where-blinding-occurs).

Please note that full labelling per regulation 46(1) of the Clinical Trials Regulations must be used where an authorised IMP is modified or is being used outside the terms of its authorisation. This includes where an authorised product is repackaged (e.g. de-blistered, repacked and labelled) to support blinding or treatment compliance.

IMPs that are not authorised in the UK but are authorised in the EU or an ICH region

If an IMP to be used in a clinical trial is unauthorised in the UK but has an EU or ICH region authorisation, by default it must have full labelling per regulation 46(1) of the Clinical Trials Regulations.

However, there are certain circumstances in which reduced labelling can be used for IMPs that are not authorised in the UK but are authorised in the EU or an ICH region. In these cases, the sponsor may submit a request to vary the labelling requirements (https://www.gov.uk/guidance/clinical-trials-for-medicines-labelling#varying-or-disapplying-labelling-requirements) as part of the application for clinical trial approval, which would allow reduced labelling to be used. These circumstances include:
- if the IMP is unmodified, is used according to the terms of its EU or ICH region authorisation, and is exclusively administered in a hospital or health centre taking part in the clinical trial, the sponsor may request that the IMP is labelled with the same information as an IMP with a UK authorisation used only in a hospital or health centre taking part in the trial
- if the IMP is unmodified, is used according to the terms of its EU or ICH region authorisation, and the pre-printed original pack labelling information is in English, the sponsor may request that the IMP is labelled in accordance with Part 13 of the Human Medicines Regulations 2012 (https://www.legislation.gov.uk/uksi/2012/1916/contents/made) and, on either the primary container or outer pack, with the words “for clinical trial use only” or equivalent wording (note that reference to a “clinical study” rather than a clinical trial would not be considered equivalent), with information to allow identification of the clinical trial, and with information to identify the sponsor and contact persons involved in the trial
Labelling for small primary containers

The labelling information above is generally expected to be applied to the primary packaging. Whenever an IMP is labelled in full in accordance with regulation 46(1) of the Clinical Trial Regulations or has abbreviated labelling in accordance with regulation 46(3) and 46(4) of the Clinical Trials Regulations, and where the primary packaging takes the form of blister packs or other small containers on which the full labelling particulars cannot be reasonably included, the full labelling may instead be applied to the secondary packaging. In this case, any small primary containers should also be labelled with the following information:
- information to identify the sponsor and contact persons involved in the clinical trial
- information to allow identification of the clinical trial, for example, the clinical trial reference code
- information linking the product to the participant, for example, the participant identification number
- route of administration (may be excluded for oral solid dosage forms)
- the common name of the active substance (or the medical product code)
- the strength and pharmaceutical form
- the contents by weight, volume or number of doses
- the batch or code number
Whenever secondary packaging is labelled in accordance with Part 13 of the Human Medicines Regulations 2012, any small primary containers should also be labelled in accordance with those regulations.

Labelling IMPs in trials where blinding occurs

Blinding is the process that keeps one or more parties involved in a trial (e.g. the sponsor, the investigator team and/or the participant) unaware of which treatment arm the participants have been randomised to. It is vital that the blind is maintained throughout the trial to ensure that no bias is introduced when making safety and efficacy assessments.

For trials in which blinding occurs:
- the labelling (including for small primary containers) should include the name of any comparator or placebo product used alongside the IMP being tested. This is mandatory where the IMP is unauthorised
- different batch numbers or expiry dates included on the packaging reveal that a difference exists between individual packs
- labels are applied in different positions on the packet or bottle
- printing on labels appears different (font, typeface, printing density) or differences in label stock are seen (discolouring, shape or size)
- consideration should be given as to what measures are necessary to protect the treatment allocation where authorised IMPs are used, including whether re-labelling or re-packaging away from the authorised livery, packaging and labelling is required
Decentralised manufactured IMPs

Please note that per regulation 46B of the Clinical Trials Regulations, the requirements in this guidance do not apply to any point of care decentralised manufactured IMP that is to be administered immediately and entirely after its manufacture. In these cases, no labelling is required, although the use of a pre-applied patient identifier on the primary packaging is advised.

In all other cases, decentralised manufactured IMPs should be labelled in the same way as conventionally manufactured IMPs.

For further guidance on decentralised manufactured IMPs, please refer to the Decentralised manufacture hub. (https://www.gov.uk/government/collections/decentralised-manufacture-hub)

Post-Qualified Person certification labelling

As described in paragraphs 33 and 42 of Annex 13 of EudraLex Volume 4, there are circumstances in which some packaging and labelling may take place after qualified person (QP) certification. This ‘post-certification labelling’ is primarily used to ensure that the right product is given to the right person, especially if the product is to be given continuously or over a long period of time. The labelling is usually performed prior to despatch, in the preparation area, or immediately prior to administration to a participant.

The circumstances in which additional labelling can be undertaken are:
- application of an identifier to ensure that a reconstituted IMP in its final container is administered to the correct participant
- application of expiry date labelling (or revised expiry date labelling)
- application of an investigator name
- application of a protocol number
Post-certification labelling should be performed at a location with an MIA(IMP) unless the risk to the quality of the product is unacceptably elevated by any required transportation to where the participant is being dosed. If this is not possible (as defined by the risk assessment) then there should be:
- a clear formalised procedure for the activity (including any sample labels and documentation to be completed)
- documented training and delegation of the activity to appropriate trial staff
The level of assurance of the quality of the final product should not be less than if this labelling were performed prior to QP certification.

Post-QP certification labelling does not need to be approved by the licensing authority.

Determining the minimum labelling requirements for IMPs used in a clinical trial

For further support in determining the minimum labelling requirements for IMPs used in a clinical trial, review Figure 1. Decision tree for determining the minimum labelling requirements for investigational medicinal products (IMPs) used in a clinical trial. (https://assets.publishing.service.gov.uk/media/68da8e8eef1c2f72bc1e4b90/Fig1._Labelling_requirements_for_IMPs_in_a_CT.pdf) (PDF, 165 KB, 1 page)

Labelling for non-investigational medicinal products used in clinical trials

Per regulation 46A of the Clinical Trials Regulations, non-investigational medicinal products (NIMPs) used in a clinical trial are, in most cases, subject to the same labelling requirements as IMPs.

As the majority of NIMPs are expected to be authorised medicinal products, used unmodified, this means that they should usually be labelled in accordance with the existing UK requirements for prescribed medicines dispensed by pharmacies set out in Part 13 of the Human Medicines Regulations 2012 (https://www.legislation.gov.uk/uksi/2012/1916/contents/made). In addition, the label should include either on the primary container or outer pack:
- the words “for clinical trial use only”, or equivalent wording
- information to allow identification of the clinical trial, for example, the clinical trial reference code
- information to identify the sponsor and contact persons involved in the clinical trial (i.e. the names and telephone numbers of the local investigator and sponsor or, if a telephone number cannot be provided, a clear strategy on how the person can be reached in a timely manner)
However, unlike IMPs, NIMPs authorised in the UK, EU or an ICH region that are to be exclusively administered in a hospital or health centre taking part in the clinical trial cannot be labelled in accordance with regulation 46(3) and 46(4). These non-investigational medicinal products must instead be labelled either:
- in accordance with the existing UK requirements for prescribed medicines dispensed by pharmacies set out in Part 13 of the Human Medicines Regulations 2012 (https://www.legislation.gov.uk/uksi/2012/1916/contents/made) (and ideally, with the additional information listed above), if the pre-printed original pack labelling information is in English
- otherwise in accordance with regulation 46(1) of the Clinical Trials Regulations
Submitting labelling for investigational medicinal products and non-investigational medicinal products for approval by the licensing authority

Labelling for all IMPs and NIMPs to be used in the clinical trial should be included with the application for clinical trial approval. These labels should be clear, legible, and of a suitable size to aid participant compliance (with due regard for the participant population, e.g. those with sight issues).

However, submission of detailed labelling information is not needed where the IMP or NIMP is labelled is in accordance with the existing UK requirements for prescribed medicines dispensed by pharmacies set out in Part 13 of the Human Medicines Regulations 2012 (https://www.legislation.gov.uk/uksi/2012/1916/contents/made)Human Medicines Regulations 2012. In this case, confirmation that this labelling approach will be followed is sufficient. Please note that full labelling, or confirmation that labelling will be in accordance with Part 13 of the Human Medicines Regulations 2012 (https://www.legislation.gov.uk/uksi/2012/1916/contents/made), must still be submitted where an IMP is assembled without a manufacturer’s authorisation under regulation 37 of the Clinical Trials Regulations (i.e. in a hospital or health centre by a doctor or pharmacist or a person acting under the supervision of a pharmacist, where the IMP is being used exclusively in that hospital or health centre or any other that is a trial location for the same clinical trial in which the product is to be used).

Varying or disapplying labelling requirements

At the same time as submitting an application for clinical trial approval (https://www.gov.uk/guidance/clinical-trials-for-medicines-apply-for-approval-in-the-uk#applying-for-approval-for-a-clinical-trial), the applicant may request an exemption from or variation to any of the labelling requirements described in this guidance. This should be done by including the request, with justification, in the labelling documents included in the application.

For example, the applicant might submit a request to disapply the requirement to label an unauthorised IMP with a warning to store the product out of the reach and sight of children, providing the justification that the IMP is for use in a trial where it is administered only by a healthcare professional and is never taken away from the trial site.

If this request is agreed by the licensing authority, the applicant will be informed of this at the same time as the outcome of the application for approval is communicated.

Please note that where a request to vary or disapply the labelling requirements for an IMP or NIMP is made for a trial that is notifiable (https://www.gov.uk/guidance/clinical-trials-for-medicines-notifiable-trials) per regulation 11A of the Clinical Trial Regulations, this must be specified in the cover letter and may result in the licensing authority choosing to exercise its right to undertake a full review of a notifiable trial before issuing a decision. The exception to this is where the request is to vary or disapply the labelling requirements for an authorised IMP that is to be exclusively administered in a hospital or health centre taking part in the trial. In this case, the trial may be submitted for automatic authorisation. The licensing authority will not give notice that the request to disapply or vary the labelling requirements has been accepted, but the request should still be treated as approved.

If an exemption from or variation to any of the labelling requirements described in this guidance is not requested at the time of approval, the sponsor may subsequently request this via a Route A substantial modification (https://www.gov.uk/guidance/clinical-trials-for-medicines-modifying-a-clinical-trial-approval#applying-for-approval-of-a-substantial-modification).

Modifying the approved labelling while a clinical trial is ongoing

If the sponsor wishes to make a change to the text of the labelling of the IMPs or NIMPs after approval for the clinical trial has been given by the authorities, and that change is considered to be a substantial modification (https://www.gov.uk/guidance/clinical-trials-for-medicines-modifying-a-clinical-trial-approval#types-of-modification), they must submit a Route A substantial modification (https://www.gov.uk/guidance/clinical-trials-for-medicines-modifying-a-clinical-trial-approval#applying-for-approval-of-a-substantial-modification).