A study published in Cannabis & Cannabinoid Research found that a CBD-containing topical formulation was associated with reduced localized pain and improved functionality among women with fibromyalgia.

The study, conducted by researchers from the Institut Clínic de Neurociències at Hospital Clínic de Barcelona, included 30 women with fibromyalgia and clinically relevant localized pain caused by musculoskeletal, neuropathic or cutaneous comorbidities.

Participants self-applied a commercially available topical formulation containing cannabidiol (CBD) to a painful area every eight hours for 12 weeks. Researchers assessed outcomes at the start of the study, then again at four weeks and 12 weeks.

According to the study, all participants reported full adherence to the application schedule at both follow-up visits, and no adverse events or side effects were reported.

Researchers found that localized pain was significantly reduced at four weeks, with the improvement sustained through 12 weeks. By the end of the study, 60% of participants achieved what researchers considered a minimal clinically important difference in localized pain.

Functional capacity also improved, with 50% of participants exceeding the minimal clinically important difference threshold at four weeks.

The study also found progressive reductions in Widespread Pain Index and Symptom Severity Scale scores, and a lower proportion of participants met the 2010 American College of Rheumatology diagnostic criteria for fibromyalgia at the 12-week follow-up.

However, researchers noted that generalized pain, fatigue, anxiety and depression did not show significant changes.

“Topical application of a CBD-containing formulation was feasible and was associated with improvements in localized pain and functionality in this exploratory single-arm study,” the researchers concluded.

They cautioned that the findings should be interpreted carefully due to the study’s limitations, including its small size, lack of a control group and the multicomponent nature of the product used.

The researchers said the results should be considered exploratory and hypothesis-generating, while providing effect size estimates and methodological guidance for future randomized controlled trials examining topical cannabinoids for fibromyalgia.