Medical Cannabis For Endometriosis: What Does The Evidence Tell Us?
Written by Hannah Barnett, Drug Science Head of Communications
Endometriosis is a chronic condition where tissue similar to the lining of the uterus grows outside of it, causing scarring, inflammation, and often debilitating pelvic pain. Approximately 10% of women and girls of reproductive age are affected by endometriosis, and limited awareness and the wide range of symptoms can contribute to substantial delays in diagnosis.
No cure for endometriosis currently exists. Instead, treatment primarily focuses on pain management, commonly with nonsteroidal anti-inflammatory drugs, hormonal therapies, and surgery. However, the effectiveness of these options varies greatly, and many individuals continue to experience persistent pain.
Medical cannabis as a treatment option
Faced with minimal pain relief using existing therapies, people are increasingly considering how medical cannabis could help manage symptoms. The body’s endocannabinoid system is involved in processes including pain signalling, inflammation and immune function, and research suggests it may also play a role in endometriosis. Cannabinoids such as THC and CBD interact with this system and other biological pathways involved in pain and inflammation, providing a rationale for further investigation of their potential therapeutic effects.
Patient-reported evidence suggests that individuals are using medical cannabis as a complementary or alternative approach to symptom management, particularly for pain. Surveyed endometriosis patients rated medical cannabis as an effective self-management strategy offering improvements in pelvic pain, sleep and gastrointestinal symptoms. Some patients also note a reduction in their use of conventional pain medication.
These outcomes are also reflected in prospective observational studies, including research from the UK Medical Cannabis Registry and New Zealand, which have reported improvements in pain, quality of life and other endometriosis-related symptoms among patients prescribed medical cannabis. A two-year study from the UK Medical Cannabis Registry also reported sustained improvements in pain, quality of life, anxiety and sleep over the two-year follow-up period.
Like what you're reading? Help us keep the conversation going.
By joining the Drug Science Community, you directly support independent research and evidence-led conversations like these.
Get involved from just £5 a month.
Findings from T21
Findings from Drug Science's Project Twenty21 (T21) adds additional evidence into the experiences of people with endometriosis who have been prescribed medical cannabis. Among the 41 patients with follow-up data on well-being who reported endometriosis as their primary or secondary condition for medical cannabis treatment, statistically significant improvements were observed across all four measures: quality of life, general health, mood and sleep. Among the 31 participants with available pain data, mean pain severity scores decreased from 6.0 to 5.0, while pain intensity scores decreased from 7.0 to 5.4. Both reductions were statistically significant.
Although the T21 sample is relatively small and the absence of a control group prevents the improvements from being attributed directly to medical cannabis, the results provide further real-world evidence of improvements in pain and well-being among patients living with endometriosis.
Future research
Evidence on medical cannabis for endometriosis remains largely observational and is based on relatively small patient populations. While patient reports, registry data and the potential biological mechanisms through which cannabinoids may influence pain and inflammation provide grounds for further investigation, they cannot establish whether medical cannabis itself causes the improvements observed.
Well-designed clinical trials are now needed to determine whether medical cannabis is an effective treatment for endometriosis-related symptoms, which patients may benefit, and which formulations and doses are most appropriate. Further research should also examine long-term safety and effectiveness.
For a condition where many patients continue to experience significant symptoms despite existing treatments, these are important questions to answer.