ced pexels 8438922

`Endocannabinoid System: CBD vs Placebo in Fibromyalgia`

Clinical Takeaway

In this randomized, double-blind, placebo-controlled trial, CBD did not demonstrate superiority over placebo in reducing pain among patients with fibromyalgia. These findings highlight the current lack of robust clinical evidence supporting CBD as an effective treatment for fibromyalgia pain. Patients and clinicians should weigh this evidence carefully when considering CBD as part of a fibromyalgia management plan.

`Endocannabinoid System: CBD vs Placebo in Fibromyalgia`

#7 Cannabidiol versus placebo in patients with fibromyalgia: a randomised, double-blind, placebo-controlled, parallel-group, single-centre trial.

Citation: Rasmussen Marianne Uggen et al.. Cannabidiol versus placebo in patients with fibromyalgia: a randomised, double-blind, placebo-controlled, parallel-group, single-centre trial.. Annals of the rheumatic diseases. 2026. PMID: 40846590.

Study type: Journal Article, Randomized Controlled Trial  |  Topic area: Cannabidiol  |  CED Score: 11

Design: 5 Journal: 0 N: 2 Recency: 3 Pop: 2 Human: 1 Risk: -2

Why This Matters
This is the first rigorous randomized controlled trial to evaluate CBD’s efficacy in fibromyalgia, a condition for which patients currently lack evidence-based pharmacologic alternatives to conventional analgesics and SNRIs. A positive result would provide clinicians with an objective safety and efficacy profile to guide patient selection and dosing, while a negative result would help curb off-label CBD use and redirect patients toward established treatment protocols. Either outcome addresses a significant gap in the literature given the widespread patient use of CBD for fibromyalgia pain despite minimal clinical validation.

Quality Gate Alerts:

  • Preclinical only

Abstract: OBJECTIVES: Cannabidiol (CBD) is used to alleviate fibromyalgia pain despite limited evidence for efficacy. This study assessed the efficacy and safety of CBD vs placebo in patients with fibromyalgia, hypothesising that CBD would be superior to placebo in reducing pain. METHODS: In this single-centre, double-blind, randomised, placebo-controlled trial, patients diagnosed with fibromyalgia were recruited from a specialised outpatient clinic in Denmark. Eligible participants were randomised 1:1 and stratified by sex, defined as biological sex assigned at birth based on physical anatomy. Age (<45 vs โ‰ฅ45), and pain level (<7 vs โ‰ฅ7) on a 0 to 10 numeric rating scale (NRS) to receive 50 mg plant-derived CBD or placebo tablets. The primary outcome was change in pain intensity at week 24, assessed on the NRS pain subitem in the revised Fibromyalgia Impact Questionnaire in the intention-to-treat population. Adverse events were monitored throughout the study in the safety population. RESULTS: Of 273 participants screened for eligibility, 200 were included and randomised to receive CBD (n = 100) or placebo (n = 100). At week 24, mean change in pain intensity was -0.4 points (95% CI: -0.82 to 0.08) in the CBD group and -1.1 points (95% CI: -1.53 to -0.63) in the placebo group, corresponding to a between-group difference of -0.7 points (95% CI: -1.2 to -0.25; P = .0028) favouring placebo. Adverse events were generally mild and evenly distributed between groups. CONCLUSIONS: The findings do not support CBD 50 mg daily as an analgesic supplement for patients with fibromyalgia. CLINICALTRIALS: gov number: NCT04729179.

Clinical Perspective

๐Ÿ’Š This Danish single-centre trial provides a rigorous placebo-controlled evaluation of cannabidiol for fibromyalgia pain, a condition where patients often seek cannabis products due to limited conventional options. While the randomized double-blind design strengthens internal validity, the single-centre recruitment limits generalizability, and fibromyalgia’s heterogeneous presentation and high placebo response rates complicate interpretation of any observed effects. The study’s completion status and effect size data will be critical to assess whether CBD offers meaningful clinical benefit beyond placebo, particularly given the substantial psychosocial and nocebo components inherent to fibromyalgia management. When counseling patients about CBD for fibromyalgia, practitioners should acknowledge both the mechanistic plausibility and current evidence gaps, emphasizing that even if this trial shows superiority over placebo, CBD would likely function as one component within a multimodal pain management strategy rather than as monotherapy.

 |