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What is T21?

T21 allows patients to access certain qualifying medical cannabis products at a discounted price while collecting data to build up the real world evidence on the effects of Cannabis-Based Medicinal Products (CBMPs). 

Drug Science will use the data from T21 to provide evidence for NHS funding of medical cannabis treatment.

Receive monthly updates including our latest data findings.

About T21

Drug Science publishes peer reviewed research, reports, and articles to provide clear, evidence-based information without political or commercial interference.

Why join T21?

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You help us move closer to our ultimate goal of access to medical cannabis on the NHS by providing us with your data. We do this by asking patients to fill out a few questionnaires once every 3 months.

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You receive at least 5% off the price of your product if you're prescribed from the T21 Formulary.

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You can trust that your prescribed product will be high quality, as the study is supported by multiple industry partners offering EU GMP-certified products.

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Drug Science is completely independent and observational, so there is no bias when it comes to which clinic you choose or what you will be prescribed.

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You’re in safe hands, with some of the UK’s leading medical cannabis clinicians prescribing at our participating clinics.

Which are the most common conditions that can be treated with medical cannabis?

  • o Arthritis
    o Back and/or neck pain
    o Complex regional pain syndrome (CRPS)
    o Ehlers-Danlos Syndromes (EDS)
    o Endometriosis
    o Fibromyalgia
    o Joint pain
    o Musculoskeletal pain (MSK)
    o Neuropathic pain/nerve pain
    o Other condition that causes chronic pain

  • o Autism spectrum disorder (ASD)
    o Alzheimer’s disease
    o Cluster headaches

    o Chronic Fatigue Syndrome/ME
    o Epilepsy
    o Functional neurological disorder (FND)
    o Migraines
    o Motor neurone disease (MND)
    o Multiple Sclerosis
    o Muscle spasms
    o Parkinson’s disease
    o Tourette’s syndrome
    o Tremors
    o Stroke

  • o Agoraphobia
    o Appetite disorders (ex. anorexia)
    o Attention deficit hyperactivity disorder (ADHD)
    o Generalised Anxiety Disorder (GAD)
    o Insomnia/sleep disorders
    o Major Depressive Disorder (Depression)
    o Obsessive Compulsive Disorder (OCD)
    o Panic disorder
    o Post-Traumatic Stress Disorder (PTSD)
    o Social anxiety disorder (social phobia)
    o Substance Use Disorder
    o Other condition that causes anxiety

  • o Crohn’s and/or ulcerative colitis
    o Irritable bowel syndrome (IBS)

  • o Cancer-related anxiety
    o Cancer-related appetite loss
    o Cancer-related depression
    o Cancer-related pain
    o Chemotherapy induced nausea and vomiting

  • o Palliative care pain
    o Palliative care anxiety

  • o Restless legs syndrome

T21 Clinics

Am I eligible?​

We welcome any patient with a legal medical cannabis prescription, regardless of whether or not their prescribed product(s) is on our formulary.

  • You must have a diagnosed condition that can be treated with medical cannabis to join T21. Select from the most common conditions below to choose a suitable T21 clinic to contact. Drug Science does not register patients directly.

  • You don’t need a referral from your doctor to make an appointment. Your chosen clinic will help you locate your medical records for confirmation of your diagnosis.

  • Some clinics may have additional eligibility criteria such as having tried two other forms of treatment or therapies for your condition which have proven ineffective.

  • If you are already registered with a participating clinic (listed below), you can ask the clinic to register you with T21.

  • If you are already registered on T21 and change to a non T21 participating clinic, you can still take part in the project by completing the questionnaires that are sent to your email every 3 months.

Frequently Asked Questions

  • Before:

    You will need to make sure that you meet the eligibility criteria of your chosen clinic and inform them that you wish to participate in T21 before your first appointment with a clinician (we also recommend you remind your clinician at your first appointment).



    Most appointments are done virtually, although some clinics do also offer face-to-face. The doctor will work with you to complete an initial assessment and questionnaire to establish your existing condition, symptoms, any previous/current medications or therapies and any history of cannabis use. It is up to the doctor to decide whether to prescribe medicinal cannabis products based on this initial assessment – attending a consultation does not guarantee a medical cannabis prescription will be issued.



    Your prescription will be couriered to you in the post once payment has been made to the dispensing pharmacy as advised by your clinic. Your clinic will decide how often you need to see a doctor or nurse and advise you of any follow-up appointment schedule – this is a minimum of once every three months. Your data will be collected every three months via emails from Sail, our data collection system for the project. You must fill out these questionnaires and attend your follow-up consultations in order to remain with T21.

  • Patients registered with T21 benefit from a minimum 5% discount off all products included on the T21 Formulary. Prescription costs are determined by the producers and dispensing pharmacies. Please speak to your clinician should you require any further details on pricing. You have the right to refuse the prescription if you’re unable or unwilling to pay. Consultation and repeat prescription costs are set by the clinic – simply view our clinics below, to find out their prices.

  • The T21 formulary includes a range of indica & sativa flower products with varying CBD & THC ratios as well as a number of different oils. These are produced by our project partners:

  • During the initial appointment with your clinician, you must inform them of your intention to participate in T21. Providing you are then prescribed products from the T21 Formulary, your clinician will then notify the dispensing pharmacy so a 5% minimum discount can be applied to your prescription. If you have reason to believe that the discount has been missed from your prescription cost, please speak to your clinician before making any payments. You can also email the T21 team at

  • We recommend reading the advice from PLEA on How to Get Started with Medical Cannabis Flower and Oil. The only medically licensed vaporisers available in the UK are the Mighty and the Volcano from Storz & Bickel. You can get a 10% discount on these devices through the Newgrove Pharmacy website if you are participating on T21 with code TWENTY21.

  • No. You can specify the pharmacy you would like to use to dispense your prescription, however, this might incur additional charges. We help T21 prescribers understand which pharmacies do not add any extra costs.

  • You can be prescribed any medical cannabis product available in the UK and still take part in T21. The cost of your product will be determined by its producer. If you wish to benefit from the T21 discount, you can ask your clinician if there is a suitable equivalent product listed on the T21 Formulary onto which you could move.

  • All T21 clinics that are participating in the study are listed above. If your clinic is not listed as a T21 participant, you can still take part in T21 by emailing us at Stay tuned to the T21 newsletter for updates on new clinics.

  • Yes. We understand that sometimes it is necessary for patients to move to a different clinic. Scroll down to choose a new clinic, then contact the new clinic making it clear that you’re already with T21 and which clinic you need to be moved over from. Your new clinic will need written confirmation from you before they notify our technical team to move your data across smoothly.

    Read your rights as a patient to changing clinic. 

  • Your data is collected through questionnaires that are sent out via email every three months by our data collection system, Sail. It is then anonymised for analysis by the Drug Science team. We use this data to publish monthly figures and data insights in the T21 newsletter, as well as more detailed research which we publish in medical and scientific journals to help influence policy change.

  • T21 is the only cannabis registry that is independent of prescribers and clinics, so our research findings cannot be inappropriately influenced by commercial interests. Our findings, therefore, carry more weight towards a future NHS acceptance of medical cannabis than those from alternative, commercially-associated clinics.

  • Last year, we published data on the characteristics of Chronic Pain patients on T21. Before that, we demonstrated through T21 data that medical cannabis improves Quality of Life by over 50%. In addition to peer-reviewed papers, we publish monthly data nuggets which offer a quick deep dive into what we’re finding in the data. Founding member of T21, Khiron Life Sciences, has published two peer-reviewed papers focusing on patients prescribed Khiron products to treat chronic pain, anxiety and personality disorders.

  • Yes. You can give your data to multiple registries at the same time – this shouldn’t affect your participation in T21.

  • Drug Science T21 team – we’re only a small team so we’re unable to answer every email we receive, but if your query cannot be answered by a clinic or one of the organisations below, you can email us at

    Medical Cannabis Patients Association (MCPA) – hopes to create awareness and to educate everyone about the benefits of cannabis based prescribed medicines.

    Seed our Future – a national movement that uses non-violent civil disobedience in an attempt to bring about mass awareness of the unsubstantiated laws and regulations surrounding the Cannabis plant and how this affects us all

    Medcan Family Foundation – an educational hub for parents and carers looking to learn more about cannabis and how it could potentially help their children. It taps into the latest research and is in collaboration with the world leaders in cannabis use for paediatric care.

    Release – the team at Release provides free non-judgmental, specialist advice and information to the public and professionals on issues related to drug use and to drug laws. Helpline: 020 7324 2989 or email:

The front cover of the patients guide to medical cannabis

Know Your Rights: Medical Cannabis in the UK

Cannabis-Based Prescribed Medicines have been available in the UK since 2019. These medicines are permitted for the treatment of various medical conditions, provided an individual demonstrates exceptional clinical necessity and has exhausted at least two alternative treatment options without success. 

The rollout of Cannabis-Based Prescribed Medicines has been tumultuous and has left patients, employers, and UK police forces confused regarding their rights and the law. This document aims to alleviate some of that confusion.

*Important Note for Readers

This information is provided as a guide for educational purposes only. Whereas every effort has been made to ensure its accuracy, it is important to understand that is not legal advice, and the information must not be relied upon as such. This is because the information set out herein is not nearly detailed or tailored enough to address all the legal considerations that may arise in any specific circumstances. Some information has been paraphrased and additional legal topics have been omitted for ease of reading, as have many exceptions to the rules set out herein. We would therefore encourage anyone facing issues of a legal nature to contact Mackrell.Solicitors or another suitably qualified law firm for bespoke advice.

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