Cannabidiol Shows No Significant Analgesic Effect in Fibromyalgia in Single-Centre Trial
Denmark: A single-center trial published in Annals of the Rheumatic Diseases has found that cannabidiol (CBD) 50 mg daily did not reduce pain in fibromyalgia patients compared to placebo. While study data slightly favored the placebo group, the differences were not considered clinically meaningful, providing little support for the use of CBD as an analgesic in this population.
Marianne Uggen Rasmussen from the Parker Institute, Bispebjerg and Frederiksberg Hospital, Denmark, and colleagues conducted the randomised, double-blind, placebo-controlled trial to evaluate the efficacy and safety of CBD in patients with fibromyalgia. Despite increasing interest in CBD as a potential pain-relief therapy, evidence regarding its benefits in fibromyalgia remains limited.
The trial recruited participants from a specialised outpatient clinic in Denmark. Eligible patients were randomly assigned in a 1:1 ratio to receive either 50 mg of plant-derived CBD or a matching placebo tablet. Randomization was stratified by sex, age (<45 vs ≥45 years), and baseline pain levels (<7 vs ≥7 on a 0–10 numeric rating scale). The primary outcome measured was change in pain intensity over 24 weeks, assessed using the numeric rating subitem of the revised Fibromyalgia Impact Questionnaire (FIQ). Adverse events were monitored throughout the study.
The key findings of the study were as follows:
- Of the 273 patients screened, 200 met the inclusion criteria and were randomized equally into the CBD and placebo groups.
- At week 24, the CBD group showed a mean reduction in pain intensity of −0.4 points.
- The placebo group experienced a slightly greater mean reduction in pain intensity of −1.1 points.
- The between-group difference was −0.7 points, favoring the placebo.
- The difference between groups was not considered clinically meaningful.
- Adverse events were mostly mild and occurred at similar rates in both groups.
The researchers concluded that daily supplementation with 50 mg of CBD did not confer significant analgesic benefits for fibromyalgia patients. They emphasized that while CBD is increasingly used in real-world settings for pain management, these findings highlight the importance of evidence-based guidance before recommending CBD as part of fibromyalgia treatment.
The trial’s rigorous design, including randomization, double-blinding, and stratification by key demographic and clinical factors, strengthens the reliability of the findings. However, the authors note that further research may be needed to explore different doses, formulations, or longer-term treatment effects to fully understand the potential role of CBD in chronic pain management.
"Overall, the study provides high-quality evidence indicating that low-dose CBD should not be relied upon as a pain-relief therapy for fibromyalgia, reinforcing the need for continued investigation into effective and safe treatment options for this complex and challenging condition," the authors wrote.
Reference:
Rasmussen MU, Christensen R, Wæhrens EE, Henriksen M, Duhn PH, Bliddal H, Amris K. Cannabidiol versus placebo in patients with fibromyalgia: a randomised, double-blind, placebo-controlled, parallel-group, single-centre trial. Ann Rheum Dis. 2025 Aug 21:S0003-4967(25)04238-4. doi: 10.1016/j.ard.2025.07.008. Epub ahead of print. PMID: 40846590.
Next Story