Medical Cannabis for Endometriosis: the Evidence So Far

In 2025, the World Health Organization estimated that it affects 190 million people worldwide — around one in 10 women of reproductive age. Women wait an average of nine years before finally receiving a diagnosis. There is currently no cure, and existing treatments are focused on symptom management. 

The treatment gap has led to increased interest in alternative or complementary medicines like medical cannabis. 

Cannabinoids are being investigated partly because of the role the endocannabinoid system plays in pain signalling and immune activity. However, research has mainly focused on symptom management rather than whether these medicines can address the underlying disease. 

For example, a September 2026 review examining mechanisms involving inflammation, pain, and lesion proliferation identified ‘therapeutic potential’ and reasons for further research, but did not demonstrate that cannabis shrinks lesions or changes disease progression in patients.

The current evidence base is made up predominantly of real-world evidence, including patient surveys and observational studies, with a few small and early-stage clinical trials.

In an Australian survey, endometriosis patients who described themselves as cannabis users rated its effectiveness for pain at 7.6 out of 10, while 56% reported reducing pharmaceutical medicines by at least half.

Later research highlighted inadequate symptom control, medication side effects and barriers to legal access as reasons patients turn to cannabis. These largely self-reported findings cannot establish effectiveness, but demonstrate that further controlled research is needed and emphasise the importance of medical supervision.

What do patients say about medical cannabis and endometriosis?

Data from the UK

A 2026 UK Medical Cannabis Registry analysis examined 101 patients prescribed cannabis-based medicines for endometriosis-associated pain.

Researchers reported improvements in pain, sleep, anxiety, and quality of life at follow-ups extending to 24 months. Eighteen participants reported 165 adverse events, with fatigue, lethargy, and headaches among the most frequent.

However, there was no placebo or comparison group, while the authors noted that expectations, other treatments, and changes over time could have influenced outcomes. 

The authors concluded that CBMP treatment was associated with sustained improvements in pain, health-related quality of life, sleep, and anxiety, but randomised controlled trials are required to establish efficacy and safety.

German pilot study

A study published in PLOS One on 22 September 2026 enrolled 30 patients, of whom 27 completed three months of treatment with balanced THC oral extracts.

Researchers reported improvements in pain and quality of life, alongside reductions in other analgesic use. However, the study was small and lacked a placebo group.

Its authors, including Professor Sylvia Mechsner, head of the Endometriosis Centre at Charité in Berlin, wrote: “This study provides preliminary evidence that oral CBMPs may represent a safe and effective adjunct therapy for managing pain and related symptoms in women with endometriosis. Larger randomised controlled trials are warranted to confirm these findings and establish optimal dosing strategies.”

Have randomised controlled trials tested cannabis in endometriosis?

Yes, but their findings are more mixed than the real-world evidence suggests.

In a 2025 review, researchers explicitly acknowledged the shortage of high-quality clinical-trial evidence, and said consideration should be given to ‘trialing medicinal cannabis as part of the interdisciplinary management of endometriosis’ in appropriate patients.

The Brazilian DREAMLAND trial, published in January 2026, randomised 102 participants to CBD-enriched oral oil or placebo for 10 weeks. Participants had recurrent pain after endometriosis surgery and were receiving hormonal treatment. Pain improved in both groups, but CBD was not significantly better than placebo. The trial was discontinued following a planned interim analysis because there was no clinically relevant additional benefit and mild adverse events were more frequent with CBD.

Elsewhere, an Australian feasibility trial published online in September 2025 compared combined vaporised THC-containing flower and oral CBD, oral CBD alone, and placebo oil. Researchers intended to recruit 63 participants, but only 12 were randomised. Only four completed the study, with the authors identifying the requirement to abstain from driving and a high level of participant withdrawal as major barriers. 

 

What clinical trials are currently ongoing?

ENDOCAN-1 is a UK clinical trial investigating Ananda Pharma’s MRX1 oral CBD formulation for endometriosis-associated pain.

Led by researchers at the University of Edinburgh and NHS Lothian, and funded by Scotland’s Chief Scientist Office, it aims to recruit 100 participants across NHS Lothian and NHS Grampian.

Its primary objective is feasibility, assessing eligibility, recruitment, and retention. Researchers will also estimate effects on pain and quality of life, assess safety, and examine other outcomes to inform a larger trial. It is currently listed as being in the recruitment phase. 

What does this mean for patients and clinicians?

NICE’s guidance on the treatment of endometriosis recommends hormonal treatments, such as the combined contraceptive pill or a progestogen, and sets out pathways for further treatment and specialist care. The body does not recommend the prescribing of unlicensed cannabis-based medicines for chronic pain conditions.

However, if patients have tried two previous treatments without success, they may be eligible for treatment through a private cannabis clinic.

If appropriate, cannabis-based medicines should be discussed as part of a patient’s overall care plan, taking into consideration symptoms, previous treatment responses, and potential risks, and in communication with their healthcare team.

Join the conversation at Cannabis Health Symposium

The role of medical cannabis in women’s health will be explored in a dedicated session, Addressing unmet needs in women’s health, at the Cannabis Health Symposium, taking place on 26 November 2026 at Conway Hall, London.

The event will bring together experts to discuss the latest evidence, clinical experiences and research priorities across menopause, endometriosis, PMDD and chronic pelvic pain.

Book your place here.

 

FAQs

Does CBD oil help with endometriosis pain?

Early research suggests cannabinoid medicines may help some people manage endometriosis-related symptoms, but there is not enough evidence to support CBD as a proven treatment. ENDOCAN-1 is investigating a specific oral CBD formulation, but the findings cannot automatically be applied to shop-bought oils.

Is CBD or THC better for endometriosis?

There is not enough reliable comparative evidence to say whether CBD, THC, or a combination works best.  THC can cause intoxication, while CBD does not produce the same high. Both can cause side effects and interact with medicines.

How much CBD should you take for endometriosis?

There is currently no established, evidence-based CBD dose for endometriosis. Research doses depend on the formulation and study protocol, and should not be copied as self-treatment instructions. Anyone considering CBD should discuss existing medicines, possible interactions and treatment goals with a clinician or pharmacist.

Can you get medical cannabis for endometriosis on the NHS?

Medical cannabis is not routinely recommended on the NHS for endometriosis-related chronic pain. NICE advises against offering THC-containing medicines for chronic pain and restricts CBD for chronic pain to clinical trials.