With Project Twenty21, eligible patients can access affordable medical cannabis treatment, monitored by Drug Science. The project aims to create the UK’s largest body of evidence for the effectiveness and tolerability of medical cannabis. Drug Science hope that the findings of Project Twenty21 will provide evidence for NHS funding where the benefits of treatment with medicinal cannabis is proven to outweigh the potential risks.

How can patients be prescribed medical cannabis through Project Twenty21?

Project Twenty21 is a UK registry aiming to monitor the health outcomes of patients using cannabis based medicinal products (CBMPs), creating the largest body of evidence in Europe for the safety and efficacy of CBMPs. Drug Science hope that the findings of Project Twenty21 will provide evidence for NHS funding where the benefits of treatment with medicinal cannabis is proven to outweigh the potential risks.

This real-world registry aims to target the following indications:

  • Anxiety Disorder (from any cause, including anxiety from cancer or another debilitating condition)
  • Chronic Pain (including all sources of pain, eg. cancer pain, arthritic pain, nerve pain and pain caused by conditions including but not exclusive to Fibromyalgia, Crohn’s Disease, Endometriosis and Irritable Bowel Syndrome)
  • Multiple Sclerosis (MS)
  • Post-Traumatic Stress Disorder (PTSD)
  • Substance Use Disorder
  • Tourette’s Syndrome
  • Adult Epilepsy
  • Attention Deficit Hyperactivity Disorder (ADHD)

For further information on the patient pathway and eligibility, please visit our page for patients.

Any doctor on 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 T21 team is actively helping to link up GPs who are interested in supporting the prescribing of medical cannabis with experienced clinicians who are already prescribing. As we see an increasing number of patients wishing to join the project, 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.

Our current list of clinics involved with Project Twenty21 can be found on our Clinic Directory. Clinics who come on board with us do not need to specialise in medical cannabis but might instead specialise in prescribing for a particular indication, such as pain. In addition to the clinics on our Clinic Directory, we encourage independent clinicians to join the project, but they aren’t listed on our website.


The clinics set their own pricing for the initial and follow-up consultations, and these costs must be covered by the patient. As more clinics come on board, we hope to encourage more competition in order to bring the consultation costs down for patients.

Our formulary consists of flower, oil and vape products from our T21 license producers. We ask that you prioritise prescribing product from our formulary, as only the products on our formulary are capped at £150 per month (in line with MCCS guidance). However, you are free to go off-formulary if you feel it is necessary and specify the reason at the point of prescribing.

Our current licensed producers are:

We’re actively looking to expand the number of clinics offering Project Twenty21 and to train more specialist clinicians to be able to prescribe medical cannabis in the UK. If you are a clinician specialising in one of the seven indications currently being prescribed for on T21 and would like to find out more about prescribing medical cannabis, please email prescribers@drugscience.org.uk and a member of the T21 team will be in touch.

You can either join the project under one of our existing clinics – in which case we would put you in direct contact with the best person to speak to at that clinic and help get you setup. Alternatively, you're welcome to come on board as a clinician operating completely independently or within your existing organisation.

For more information, please see our New Clinician Pack

Before commencing any training with us, we will ask you to sign a Memorandum of Understanding, to confirm that you are happy to adhere to our processes. You will then be asked to read the Project Protocol, Formulary and ‘How to get started’ pack – the latter includes useful links and resources to medical cannabis educational tools and networking.

Read the full project Protocol here.

As this is an observational study, Drug Science cannot give any advice or recommendations around the products on the T21 formulary. Instead, we encourage clinicians to:

  • Sign up for live online training with Prof. Mike Barnes – learn about cannabis history, how to prescribe, safe dosing and much more.
  • Register with the Medical Clinicians Cannabis Society (MCCS) for educational materials and the opportunity to link up with other clinicians.

To collect T21 patient data, we use an online system called Sail (built by Skylight Health). Before you receive your Sail login, a member of our T21 team at Drug Science will provide you with live Zoom-webinar training to ensure that you are confident in how to use the system. This takes around 45 minutes to complete.

As part of your Clinician’s Onboarding Pack, you will be provided with a Patient Informed Consent Form. This needs to be completed before the patient can be set up on the Sail system (to be filed securely by the clinic).


The following needs to be completed/confirmed prior to adding a patient on Sail:

  • Confirmation of primary indication
  • Confirmation of eligibility to be prescribed medical cannabis (at the discretion of the clinician)
  • Provision of informed consent


The above can be actioned by a member of admin staff, providing they have received Sail software training. The patient should be sent the questionnaire(s) according to their primary indication before the initial assessment.

The patient will already have been setup on the Sail system and filled in their patient questionnaire(s), so this data will be pre-populated in Sail for the clinician to check through ahead of the initial assessment. This should speed up patient appointment time, enabling you to get to the point of prescribing more quickly.


We ask that you make sure your patient is provided with adequate product information and any how-to guides that may be applicable to the product being prescribed – this should all be available within the Sail system.

All patient data collection for T21 is managed through the Sail system. To adhere to our project Protocol, you will be expected to conduct 3-month assessments with each T21 patient over a 24 month period (or as long as the patient is part of T21).


Patients can track their medication and symptoms in real-time using the Eva mobile app by Alta Flora, a Twenty21 founding industry partner. The app is now available to download on iOS and Android find it in the app store.


Watch demo here.


  • 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.


  • 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.