About T21
T21 (formerly Project Twenty21) was the largest non-profit led medical cannabis patient registry that ran from 2020 to the end of 2024. Data collection for this project has concluded.
About T21 (formerly Project Twenty21)
T21, across 2020 to 2024, gathered longitudinal data to support the safety and effectiveness of medical cannabis treatments in the UK. Through T21, patients were able to access a range of medical cannabis products at discounted prices, increasing accessibility while collecting valuable real-world evidence on the effects of Cannabis-Based Medicinal Products (CBMPs).
Although T21 has now concluded, Drug Science will continue to use the data collected to advocate for NHS funding of medical cannabis treatments, helping to build the case for their clinical use.
Read about the achievements of T21 here.
If you would like to support the publication of T21 data, please contact info@drugscience.org.uk.
Medical Cannabis in the UK
In November 2018, after advocacy from patient groups, medical cannabis was reclassified from Schedule 1 to Schedule 2 under the Misuse of Drugs Act 1971, making it legal in the UK. According to current laws, medical cannabis—also referred to as 'cannabis-based products for medicinal use'—can be prescribed in the UK as a 'Special' under guidance from the Medicines and Healthcare products Regulatory Agency (MHRA), but only by doctors who are listed on the General Medical Council (GMC) Specialist Register. 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 clinical necessity and has exhausted at least two alternative treatment options without success.
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 paino Autism spectrum disorder (ASD)
o Alzheimer’s disease
o Cluster headacheso 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 Strokeo 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 anxietyo 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 vomitingo Palliative care pain
o Palliative care anxietyo Restless legs syndrome
Frequently Asked Questions
A variety of medical cannabis products are available for private prescription in the UK, including flowers, oils, and vaporizers. In the UK, most medical cannabis is considered an unlicensed medication. While it is fully legal when prescribed appropriately, there are strict guidelines that must be followed to ensure both the patient and the medical cannabis specialist make the right treatment choices. You can read more about medical cannabis here.
Medical cannabis can be used to manage a range of well-known conditions. You must have a diagnosed condition that can be treated with medical cannabis to qualify for a prescription. You can check the dropdown list above for the most common eligible conditions (please note the list is not exhaustive).
You must have already tried at least two different medications to treat your condition, both of which must have been ineffective (for mental health conditions, therapy is considered a valid treatment approach).
You can find a full list of all UK clinics here.
Most appointments are done virtually, although some clinics also offer face-to-face. Your first consultation will be with a specialist consultant, lasting from 30 minutes up to 2 hours depending on the clinic. Each clinic has its own approach, but generally, the consultant will review your medical history, discuss any medications you used in the past, and talk through your treatment goals. Together, you develop a personalized treatment plan during the consultation.
Your prescription will be send 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 – there is a minimum of once every three months.
Always follow your doctor's instructions and the patient information leaflet when using your medication. If you have any doubts, please contact the clinic for clarification.
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Flower-based products are prescribed exclusively for vaporisation. If you are prescribed a flower product, you will need to order a medical device inhaler. Your doctor will specify the amount of flower (in grams) to be used per dose. The flower should be placed in the chamber of the vaporiser you purchase. 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.
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For oil-based products, please use the syringe provided with the oil to measure your dosage. Administer the oil under your tongue.
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The cost of medical cannabis products can vary depending on form (flower or oil), dosage, the balance of THC and CBD, and other factors. You can typically expect to pay ~£150 per month for medical cannabis.
Medical cannabis may cause side effects such as dizziness and drowsiness, which could impair your judgment or ability to perform tasks that require skill or focus. These effects are similar to those of other medications, including painkillers like opioids. For more information please refer to the CIC guidance here.
When traveling abroad, there may be restrictions on bringing medical cannabis into certain countries. We recommend contacting the embassy of the country you're visiting for specific guidance. If you're planning to travel, you can request a travel letter by emailing your clinic. Please note that this letter will only assist with your travel; it does not grant you permission to carry medical cannabis.
The rollout of Cannabis-Based Prescribed Medicines sometimes 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 ReadersThis 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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PatientsCannUK - an organisation founded and operated by patients, deeply committed to enhancing patient experiences and addressing all of their unique needs.
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Cannabis Patients Group UK (CPGUK) - The purpose of CPGUK is to inform patients of the ways in which they may be able to access medical cannabis. drives patient engagement for access to medicinal cannabis (CBPM).
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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 everyone.
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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.
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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: ask@release.org.uk
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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.
Prescriber Information
Any doctor on the GMC Specialist Register can prescribe medical cannabis – this is usually a hospital consultant.
GPs can prescribe under shared care arrangements under the direction of a specialist. With that in mind, the Drug Science team and the Medical Cannabis Clinicians Society (MCCS) are actively helping to link up GPs who are interested in supporting the prescribing of medical cannabis with experienced clinicians who are already prescribing. If you’re a specialist consultant, GP, prescribing nurse or prescribing pharmacist, please don’t hesitate to get in touch. As we see an increasing number of patients wishing to access medical cannabis, there is a growing need for GP support. Our hope is that, by training up more GPs in how to prescribe medical cannabis with the support of private clinicians, we can encourage policy change to allow GPs to prescribe independently in the future.
Drug Science cannot give any advice on how to prescribe, but we recommend you register with the Medical Clinicians Cannabis Society (MCCS) and sign up for Medical Cannabis Explained: live training sessions with Prof. Mike Barnes to learn about cannabis history, how to prescribe, safe dosing and much more.
Please be aware that it can take longer than you might expect to setup as a prescriber of medical cannabis products, even if you are linking with an existing clinic, because they are controlled drugs. Make sure you have followed these steps as early in the process as possible to avoid delays getting started.
To prescribe medical cannabis, you must:
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Find suitable premises as an independent prescriber or link with an existing clinic
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Apply for your ‘pink pad’ (private controlled drug prescription pad)
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Familiarise yourself with the special prescribing system
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Review your indemnity insurance arrangements
Access the MCCS guidelines on starting to prescribe medical cannabis here.
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We recommend the below educational resources:
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MedCan Hub: the MedCan Hub is a free platform developed by NHS consultants to support doctors prescribing medical cannabis. It includes a large range of tools and tips for doctors to offer better care to patients.
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Medical cannabis education slides by Drug Science on history & law and pharmacology (aimed at medical students)
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NHS advice on cannabis-based products for medicinal use FAQs
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Government advice on medical cannabis & supply of unlicensed medicinal products
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A variety of medical cannabis products are available for private prescription in the UK, including flowers, oils, and vaporizers.
The licensed medical cannabis products that can be prescribed through the NHS include Epidyolex for children and adults with epilepsy, Nabilone for chemotherapy patients and Nabiximols (Sativex) for multiple sclerosis (MS).
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Drug Science: Please email info@drugscience.org.uk to speak to a member of the Drug Science team.
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Medical Cannabis Clinicians Society: We work closely with the MCCS to ensure clinicians have sufficient tools at their disposal to confidently prescribe and share their knowledge. We urge you to stay up-to-date with the MCCS educational resources and FAQs for all the latest on prescribing medical cannabis.
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Primary Care Cannabis Network: A community platform and educational tool for GPs who are interested in learning about cannabis-based medical treatments and how these may serve the needs of patients.
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T21 Data
Here you can find a top level overview of the findings from our our medical cannabis study.
Scroll to view our research output from the project, as well.
