Project Twenty21 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.

What is Project Twenty21?

Project Twenty21 allows eligible patients to access medical cannabis treatment at a capped price, and have their treatment tracked by Drug Science. 

Drug Science will use the data from Project Twenty21 to provide evidence for NHS funding of medical cannabis treatment.


How can I get medical cannabis with Project Twenty21?

Medical cannabis treatment starts with a private consultation between you and a specialist doctor from a Project Twenty21-approved cannabis clinic

During the consultation, your doctor will be happy to discuss any medical cannabis treatment which suits your needs. 

Once your prescription has been approved, the pharmacy will contact you for payment before your medication is sent to your house.

Learn more about what happens at the consultation



To enrol, you must provide your chosen clinic (not Drug Science) with a confirmed diagnosis of one or more of the following, which may be a symptom of another condition:

This information must be documented in a medical summary or referral letter from your GP practice.

*Anxiety Disorder can originate from any cause, including anxiety from cancer or another debilitating condition. 

*Chronic Pain includes 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.

Although it is not a requirement of Twenty21, some clinics may ask that you have tried two other forms of treatment or therapies for your diagnosed condition before considering medical cannabis. Whether you meet the eligibility criteria is ultimately the decision of your chosen clinic.

Doctor or physician writing diagnosis and giving a medical prescription to female Patient
Doctor or physician writing diagnosis and giving a medical prescription to female Patient

How much does medical cannabis cost?

Price Guide

Initial Consultation

£80 - £200

Follow-up Consultation

£60 - £150

Twenty21 Flower

£65 - £150

Twenty21 Oil

Up to £150

Repeat Prescription

Up to £30

Join Project Twenty21

You can now choose a clinic from our clinic directory

Clinic Directory

Alta Flora, a Twenty21 founding industry partner, has launched an app called Eva for patients who are prescribed medical cannabis. Eva enables the collection of real-time patient self-reported data on symptoms, interactions with other drugs, and effects on symptoms and Quality of Life.


The app is now available to download on iOS and Android, find it in the app store.


Watch demo here.


Eva is a support tool for the patient use only, although you can choose to share this data with your doctor at your appointments. This data cannot be accessed by Drug Science and is not at all linked to our own data collection for the project.

Patient questionnaires for the project data collection are sent out by email once the patient is registered with a clinic and has received a login for our data collection system. Please contact your clinic if you require any further support around filling out questionnaires.  

A ‘licensed medicine’ is a medicine that has a marketing authorisation from the UK Medicines & Healthcare products Regulatory Agency (MHRA) or European Medicines Agency (EMA), enabling it to be prescribed in the UK. The issue is that medical cannabis is an 'unlicensed medication', which makes it very difficult for producers to provide detailed product information and price lists because of the strict 'marketing' restrictions. Producers cannot state any claims about its benefit for medical conditions, the required dose or how to take it. Your doctor or dispensing pharmacist can answer questions on dosage and administration.


We have a range of products from these licensed producers:


The Project Twenty21 formulary now includes a range of indica & sativa flower products with varying CBD & THC ratios as well as an increased number of different oils plus some alternative options including a synthetic medication.


We are aware that the Twenty21 formulary might not suit all patients. This is why clinicians have the freedom to prescribe whatever product is best for the patient, from all the products they are able to access, if the patient’s needs are not fulfilled by a Twenty21 product.  Your health data can still be collected and submitted into our registry and you will still be part of the project.

All products available on Project Twenty21 (oil, whole flower, granulate etc.) are from licensed producers who have been awarded an GMP (Good Manufacturing Practice) licence or international equivalent. This licence indicates that the products have been grown and manufactured to the highest internationally recognised medical standards. GMP regulations are extremely strict, and GMP approval is a legal requirement for any product to be prescribed in the UK. Patients can therefore feel confident that the product they receive is continually analysed to maintain the highest possible standards, quality and consistency. These standards are audited and approved by the relevant UK authorities.

If you believe the quality of your product does not meet these standards, please submit your feedback for the producer and dispensing pharmacy via this form.


Please note that medicinal cannabis consultations are not intended for the diagnosis of a condition. Some patients may require an additional appointment at a charge if further assessment is necessary.

Patients should inform the clinic that they wish to participate in Project Twenty21 before their consultation. When contacting a clinic make it very clear that you are a Twenty21 patient to access subsidised products.

Any products prescribed which are not included in Project Twenty21 are not subsidised and will incur prescription, dispensing and delivery costs.

Before scheduling a consultation, most clinics offer a pre-assessment involving a review of patient healthcare records. Please check with individual clinics as to whether there is a charge for this.


Consultations will either be conducted remotely via telemedicine (access to video calling required) or face to face.

Patients must ensure that the doctor is aware they wish to participate in Project Twenty21.

The doctor will complete an initial assessment and questionnaire covering:

Previous and current medications for a condition
Other therapies which have been undertaken
How symptoms affect the patient’s quality of life e.g. impact on sleep, mobility etc…
Any previous cannabis use, including cannabis-based products. The clinician should be informed of:
1. What has been most effective at managing symptoms?
2. How this is taken – by oil, edibles, balm, smoking or vaporizing?
3. Any issues or side effects experienced from using cannabis previously

The doctor will decide whether to prescribe medicinal cannabis products based on the patients’ medical history and clinical need.

Attending a consultation does not guarantee a medical cannabis prescription will be provided.


Clinics will determine the frequency and cost of follow up consultation, with data collection occurring every 3 months. Patients must attend follow-up consultations to continue receiving their medication.

We have no maximum number of patients allowed onto the study. The more data we can gather, the stronger our evidence of outcomes will be, so we need more patients and prescribers to come forward and help us gather this data.

We have no fixed deadline by which people must join or leave the study. We aim to collect health data for a minimum of 2 years. Participating clinics and consultants are responsible for submitting patient health questionnaires through our data collection system.

Yes. We understand that sometimes it is necessary for patients to move to a different clinic. Simply go to our Clinic Directory 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


Our price guide should give you an idea of the costs of medical cannabis with Project Twenty21.

Project Twenty21 has partnered with licensed producers to subsidise the cost of private medical cannabis to £150 per product per month (maximum amount is capped based on dosage guidance from the Medical Cannabis Clinicians Society). Smaller quantities of product (at lower costs) are available if the maximum dosage is not required each month. Medication, dosage and costs should be discussed at your consultation.

We are aware that there has been confusion around the pricing of T21 medical cannabis products.

Flower is charged at £65 for 10g, £120 for 20g, £150 for 30g, and thereafter £50 for every additional 10g of the same flower product. Please note that we have multiple producers of flower, and that flower products from different producers are classed as separate prescriptions so will result in a higher total amount when prescribed together in the same month.

Some cannabis-based medicinal products that may be recommended by the clinician will not be subsidised through Project Twenty21. Patients can accept these medications but must expect to pay for these products at full price. Alternatively, patients can refuse these prescriptions if they are unable or unwilling to pay for these products. The prescribing doctor will send the Twenty21 medicinal cannabis prescription to the pharmacist. Patients will be contacted by the pharmacist to make payment for the medication, this process may vary for each product. Medication will be delivered to the patients’ address following payment.

To receive medication at a subsidised rate, patients must consent to have their medical data collected by Drug Science. This information will be anonymised and kept confidential. The data will be used to examine the benefits and side effects of CBMPs. We hope that this analysis will inform future medical cannabis policy in the UK.

Please note:

Consultation and repeat prescription costs are set by your chosen clinic. Clinic consultation costs are the same regardless of your condition and can be found on our Clinic Directory.

Dispensing and delivery costs (normally charged for private prescriptions) are NOT covered for any non-Twenty 21 products that you may be prescribed.

Due to epilepsy requiring high doses of CBD-dominant products, there is a separate capped maximum price for a month’s epilepsy treatment of £550. If a lower dose is required the cost could be £375. Your clinician will be able to tell you more about the specific range of products and dosages for epilepsy patients.

Patient Led Engagement for Access (PLEA) - a UK volunteer-run organisation challenging the inequalities in access to cannabis-based medicinal products. As the UK's leading medical cannabis patient advocacy group, PLEA provides support and advice to patients through events and high quality online resources hosted on their website. Become a community member for free here.

MedCan Support - 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: 

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 above, you can email us at