CBD and fibromyalgia: what a 200-patient trial found

Fibromyalgia combines widespread, lasting pain with fatigue and sleep problems. The Inserm collective expert review published in October 2020 puts its frequency at 1.6% of the population in France, with a strong female majority. The report noted at the time that its management was "not codified" and mostly aimed at symptoms.

That is no longer quite true. On 10 July 2025, the French national health authority (HAS) published guidelines on diagnosis and treatment strategy. The first line relies on adapted physical activity, learning to manage the condition and staying in work. Some antidepressants and antiepileptics at low doses come second. Opioids have only an occasional, cautious place.

The strongest study on the question was published in the Annals of the Rheumatic Diseases, online in August 2025 and in the March 2026 issue. It is a randomised, double-blind trial run at a specialist centre in Denmark. Randomised means chance decides who receives the product; double-blind means neither patients nor clinicians know who receives what.

Of 273 people screened, 200 were included: 100 received 50 mg of plant-derived CBD a day as tablets, 100 a placebo, for 24 weeks. The main outcome was the change in pain, scored from 0 to 10 in a standard fibromyalgia questionnaire.

At week 24, pain had fallen by an average of 0.4 point in the CBD group and 1.1 points in the placebo group. The 0.7-point gap is statistically significant, in favour of placebo. Side effects were mostly mild and similarly spread across both groups. The authors conclude that their findings "do not support" CBD at 50 mg a day as an add-on painkiller in fibromyalgia.

The trial has limits: one dose, one centre, one country. It says nothing about other doses or other forms. None of the reviews cited by the HAS included a trial of this size on CBD alone, and this one shows no effect.

Before 2025, the data mostly concerned products containing THC.

A Dutch study published in Pain in 2019 had 20 patients inhale, in a single session, three pharmaceutical cannabis varieties, one of them rich in CBD, and a placebo variety. None did better than placebo on spontaneous pain. The authors also observed that CBD raised blood levels of THC while reducing its pain-relieving effect.

A systematic review published in 2023 in Biomedicines pooled four randomised trials and five observational studies, 564 patients in all. The trials mostly tested nabilone, a synthetic cannabinoid close to THC, and inhaled cannabis. The authors describe the evidence for a short-term fall in pain as "low quality".

The HAS reviewed this work in the evidence report behind its guidelines. It cites a Cochrane review limited to two trials and 72 participants, without enough data to conclude. It notes that the European rheumatology body (EULAR) does not recommend cannabinoids, for lack of data.

Our article on what clinical studies really say about CBD explains how to read this kind of result.

The HAS conclusion is clear: the data are insufficient to recommend the use of cannabinoids in fibromyalgia. The same text adds that CBD products sold over the counter have not been assessed for quality, composition or harmfulness, and that they do not have the status of medicines.

Medical cannabis is a separate matter. The pilot scheme run by the ANSM, the French medicines agency, covered five conditions, including refractory neuropathic pain, painful spasticity in multiple sclerosis and some drug-resistant epilepsies. Fibromyalgia was not one of them. The move to a permanent framework is under way: our article on the rollout of medical cannabis follows the timetable.

The only CBD-based medicine authorised in France is Epidyolex, prescribed for rare and severe forms of epilepsy: Lennox-Gastaut and Dravet syndromes, and tuberous sclerosis complex. Our update on Epidyolex and the research describes that framework.

A CBD product sold freely cannot claim any effect on a disease. The state of research would not allow it either: the only large trial of CBD alone is negative. We therefore present none of our products as an answer to fibromyalgia.

Two precautions apply to anyone on medication. CBD can interact with some medicines, including antiepileptics, a class prescribed as second-line in fibromyalgia: our article on CBD drug interactions explains the mechanism. And your doctor remains the person to talk to about any decision on your care.