Living with ongoing, long-term pain can make everyday life exhausting, impacting everything from physical mobility and mental health to getting a decent night’s sleep.
Standard treatments, including physical therapy or everyday over-the-counter painkillers, may not provide enough relief for everyone. This can lead people to explore different options for pain management, including medical cannabis.
Medical cannabis has been legally available on prescription in the UK from specialist doctors since November 2018. [1] While medical cannabis may not be suitable for everyone, research suggests it may provide modest improvements in pain and quality of life for some patients with chronic pain. [2,3]
In this article, we break down what medical cannabis is, how it works, the emerging evidence behind it, and what you need to know if you are considering exploring it as an option.
Understanding chronic pain is more than just a symptom
Chronic pain is pain that persists or recurs for longer than three months, extending well past the normal time it takes for an injury or illness to heal. [4]
While acute pain can serve a vital biological purpose by acting as a warning signal to pull your hand away from a hot stove or protect a sprained ankle, chronic pain can stem from a wide range of underlying causes, including nerve damage (neuropathy), musculoskeletal conditions, osteoarthritis and fibromyalgia.
In the UK, chronic pain is a major public health issue, affecting people both physically and economically. Chronic pain affects between 35% and 51% of the UK population, with one systematic review estimating that this could represent nearly 28 million adults. [5]
For millions, managing this daily reality can require complex care strategies, often involving a mixture of conventional medical treatments and other approaches.
What about sleep and quality of life?
Pain intensity is only one measure of whether treatment is helping.
For patients living with persistent pain, improvements in areas such as sleep, movement and the ability to manage everyday activities can also be meaningful.
The 2021 BMJ review found that non-inhaled medical cannabis or cannabinoids probably resulted in a small improvement in sleep quality and a very small improvement in physical functioning compared with placebo. [2]
Real-world studies have also reported changes in patient-reported outcomes including pain, sleep and quality of life following treatment with medical cannabis.
Conventional treatments and their limitations
For decades, modern medicine has relied primarily on several categories of pharmaceutical treatments to help patients manage chronic pain.
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)
Medications like ibuprofen can help reduce inflammation and pain. However, frequent or long-term use can increase the risk of gastrointestinal complications, including ulcers and bleeding, as well as cardiovascular complications. [6]
Opioids
Strong prescription painkillers such as codeine, tramadol or morphine are sometimes used for severe pain. While opioids can be effective for some types of pain, long-term use carries risks including tolerance, physical dependence, misuse and other side effects. There is also limited evidence supporting their long-term effectiveness for chronic pain. [7]
Gabapentinoids
Medications like pregabalin or gabapentin are commonly prescribed for nerve-related pain. However, they can also cause side effects and carry recognised risks of misuse, dependence and withdrawal problems, particularly when treatment is stopped suddenly. [8]
Because of these risks, coupled with a lack of robust evidence proving that these drugs work well over many years for some forms of chronic pain, NICE advises against prescribing these medicines for chronic primary pain. [4]
When standard medications fail to provide adequate relief or cause intolerable side effects, people naturally begin considering .alternative options. This growing search is one reason why interest in medical cannabis has risen significantly over recent years.
Yet while some patients report significant benefits, others remain sceptical, with scientists continuing to study where cannabis-based medicines can fit into modern medicine.
How is medical cannabis different to street cannabis?
It is important to distinguish between medical cannabis prescribed through a specialist clinic and street-bought cannabis.
Street-bought cannabis is not produced to the pharmaceutical standards. It can contain potentially dangerous contaminants including microbes, pesticides and heavy metals. [9]
Street-bought cannabis can also have unpredictable levels of its active ingredients, so you may not know exactly what you are consuming.
In contrast, medical cannabis products are manufactured and supplied through regulated channels, with defined concentrations of their active ingredients. This provides greater consistency than street-bought cannabis. [1]
The core active compounds of medical cannabis: THC and CBD
The cannabis plant contains dozens of active compounds known as cannabinoids, but two primary compounds dominate clinical research and medical applications:
THC (Delta-9-tetrahydrocannabinol)
THC is the main psychoactive compound in cannabis. It acts on cannabinoid receptors in the body and brain and can affect pain processing and other functions. [10]
THC can cause intoxication (a “high”), drowsiness, dizziness, impaired concentration or anxiety, particularly at higher doses. [2,10]
CBD (Cannabidiol)
CBD is not intoxicating in the same way as THC. It interacts with a range of receptors and signalling systems in the body, including parts of the endocannabinoid system. [10]
Research into CBD’s potential effects on pain, inflammation and other symptoms is ongoing. However, laboratory evidence does not automatically mean that CBD will provide meaningful pain relief in people, and clinical evidence varies depending on the condition, dose and product. [2,10]
Medical cannabis products can therefore contain different amounts and combinations of THC and CBD, depending on the individual product and the reason it is being prescribed.
How does the body respond to cannabinoids?
To understand why researchers study cannabis for pain, it helps to look at human biology. Every human being possesses a built-in cell-signalling network called the endocannabinoid system (ECS).
The ECS is involved in regulating a range of physiological processes, including:
• Pain perception
• Mood and stress
• Sleep
• Immune responses
• Appetite and other bodily functions [10]
The system relies on three main parts: endocannabinoids, which are naturally produced by our bodies; cannabinoid receptors, which are found throughout the brain, spinal cord and other tissues; and enzymes that help produce and break down these signalling molecules. [10]
When plant-based cannabinoids like THC and CBD enter the body, they interact with this existing system and other biological pathways. This may influence how pain signals and other processes are regulated.
However, scientists emphasise that simply having a biological mechanism does not automatically guarantee that a medicine will work effectively in clinical practice.
What does the scientific evidence actually say?
Real-world observational studies, alongside patient-reported outcomes, suggest that medical cannabis may help alleviate symptoms and improve quality of life for some people living with chronic pain. These studies follow patients receiving prescribed treatment in everyday clinical practice, assessing changes in pain, sleep, daily functioning and emotional wellbeing.
Real-world evidence makes an important contribution to medical cannabis research. It captures the experiences of patients with different conditions, complex medical histories and previous treatment failures, reflecting the people clinicians see in practice. It also allows researchers to study a range of prescribed products, individualised doses and treatment outcomes over time.
Project Twenty21, a UK patient registry established by Drug Science, adds to this real-world evidence. A 2024 study included 1,816 patients with chronic pain, with three-month follow-up data available for 1,058. Among those followed up, prescribed medical cannabis was associated with improvements in pain severity, the extent to which pain interfered with daily life, and aspects of general health and quality of life. As this was an observational study without a randomised control group, it cannot establish that medical cannabis caused these improvements, but it helps researchers understand patients’ experiences in routine clinical care. [11]
One of the most comprehensive systematic reviews of randomised evidence was published in The BMJ in 2021. Researchers analysed 32 randomised clinical trials involving 5,174 adults with chronic cancer and non-cancer pain. Most compared medical cannabis or cannabinoids with placebo, with follow-up ranging from one to five-and-a-half months. [2]
Overall, the results showed relatively modest benefits. Compared with placebo, non-inhaled medical cannabis or cannabinoids were associated with:
• A small increase in the proportion of patients achieving meaningful pain relief
• A small improvement in sleep quality
• A very small improvement in physical functioning
• An increased risk of some short-term side effects [2]
For pain specifically, researchers estimated approximately a 10 percentage-point increase in the proportion of patients achieving at least a minimally important improvement in pain compared with placebo. [2]
This does not mean that medical cannabis eliminates chronic pain in 10% of patients. Rather, compared with placebo, around 10 additional patients in every 100 were estimated to achieve at least the study’s threshold for a minimally important improvement.
The evidence therefore suggests that some patients may experience a worthwhile improvement.
What types of chronic pain have been studied?
Chronic pain is an umbrella term rather than a single condition, and research has included patients experiencing different forms of persistent pain.
There is particular research interest in areas including neuropathic or nerve-related pain and fibromyalgia. NICE has specifically identified fibromyalgia and persistent treatment-resistant neuropathic pain as areas where further research into CBD alongside standard treatment would be valuable. [12]
Evidence from one condition cannot automatically be applied to another. Neuropathic pain, fibromyalgia, osteoarthritis and cancer-related pain, for example, can have different underlying mechanisms and treatment pathways.
An important question for future research is therefore which patients, conditions, products and doses are most likely to benefit.
Potential risks and side effects
Like any prescription medication, medical cannabis carries potential side effects and risks that should be carefully managed.
Common short-term side effects can include:
• Drowsiness, fatigue or dizziness
• Dry mouth and changes in appetite
• Temporary changes in concentration or attention
• Changes in mood or perception
• Anxiety or light-headedness, particularly with THC-containing products [2]
Our doctors carefully choose the right product, strength and dose for each individual patient to minimise the risk of side effects. The vast majority of patients tell us they don’t experience any side effects from medical cannabis. Wellford offers follow up appointments allowing individuals to discuss their treatment and any potential dosing alterations.
Who might be eligible for medical cannabis in the UK?
Medical cannabis is not readily available on the NHS. An estimated 200,000 people in the UK access medical cannabis privately from clinics like Wellford.
Initial prescriptions for most cannabis-based medical products must be made by a specialist medical practitioner on the GMC Specialist Register. [12,1]
Generally, a patient may be considered for a specialist consultation if they have a diagnosed condition for which a clinician believes cannabis-based treatment could potentially be appropriate.
A specialist clinician will assess factors including:
• Your diagnosed condition and the type of pain you experience
• Previous treatments you have tried
• How well those treatments worked
• Any side effects or problems caused by previous treatments
• Other medicines you are taking
• Your wider medical history and individual circumstances
Ultimately, a specialist clinician must conduct an in-depth evaluation of your medical history, lifestyle and health profile to determine whether medical cannabis is safe and appropriate for you.
If you are interested in whether medical cannabis could be right for you, take Wellford’s 30-second eligibility check.
[Check your eligibility]
References
- Home Office. (2018). Rescheduling of cannabis-based products for medical use in humans. GOV.UK. Published 1 November 2018.
- Wang, L., Hong, P. J., May, C., Rehman, Y., Oparin, Y., Hong, C. J., et al. (2021). Medical cannabis or cannabinoids for chronic non-cancer and cancer related pain: a systematic review and meta-analysis of randomised clinical trials. BMJ, 374, n1034. doi:10.1136/bmj.n1034.
- Zeraatkar, D., Cooper, M. A., Agarwal, A., Vernooij, R. W. M., Leung, G., Loniewski, K., et al. (2022). Long-term and serious harms of medical cannabis and cannabinoids for chronic pain: a systematic review of non-randomised studies. BMJ Open, 12(8), e054282. doi:10.1136/bmjopen-2021-054282.
- National Institute for Health and Care Excellence (NICE). (2021). Chronic pain (primary and secondary) in over 16s: assessment of all chronic pain and management of chronic primary pain (NG193). NICE.
- Fayaz, A., Croft, P., Langford, R. M., Donaldson, L. J., & Jones, G. T. (2016). Prevalence of chronic pain in the UK: a systematic review and meta-analysis of population studies. BMJ Open, 6(6), e010364. doi:10.1136/bmjopen-2015-010364.
- Bhala, N., Emberson, J., Merhi, A., Abramson, S., Arber, N., Baron, J. A., et al. (2013). Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analyses of individual participant data from randomised trials. The Lancet, 382(9894), 769–779. doi:10.1016/S0140-6736(13)60900-9.
- Chou, R., Turner, J. A., Devine, E. B., Hansen, R. N., Sullivan, S. D., Blazina, I., et al. (2015). The effectiveness and risks of long-term opioid therapy for chronic pain: a systematic review for a National Institutes of Health Pathways to Prevention Workshop. Annals of Internal Medicine, 162(4), 276–286. doi:10.7326/M14-2559.
- Evoy, K. E., Sadrameli, S., Contreras, J., Covvey, J. R., Peckham, A. M., & Morrison, M. D. (2021). Abuse and misuse of pregabalin and gabapentin: a systematic review update. Drugs, 81(1), 125–156. doi:10.1007/s40265-020-01432-7.
- Dryburgh, L. M., Bolstridge, H. I., Filbey, F. M., & Egerton, A. (2018). Cannabis contaminants: sources, distribution, human toxicity and pharmacologic effects. British Journal of Clinical Pharmacology, 84(11), 2468–2476.
- Mlost, J., Bryk, M., & Starowicz, K. (2020). Cannabidiol for pain treatment: focus on pharmacology and mechanism of action. International Journal of Molecular Sciences, 21(22), 8870. doi:10.3390/ijms21228870.
- Athanasiou-Fragkouli, A., Lynskey, M. T., Schlag, A. K., & Nutt, D. J. (2024). Prescribed Medicinal Cannabis for the Treatment of Chronic Pain Comorbid with Depression: Real World Evidence from Project Twenty21. OBM Integrative and Complementary Medicine, 9(2), 032. doi:10.21926/obm.icm.2402032.
- National Institute for Health and Care Excellence (NICE). (2019, updated 2021). Cannabis-based medical products (NG144). NICE.
- MacCallum, C. A., & Russo, E. B. (2018). Practical considerations in medical cannabis administration and dosing. European Journal of Internal Medicine, 49, 12–19. doi:10.1016/j.ejim.2018.01.004.
