Restless leg syndrome is more common than many people realise. Research suggests it affects roughly 7 to 12 in every 100 adults in Europe and North America, and it is even more common in people with multiple sclerosis. For some, everyday treatments do not bring enough relief, so researchers continue to look for new options. A small study published in 2026 explored whether a medicine containing two cannabis compounds — tetrahydrocannabinol (THC) and cannabidiol (CBD) — might help.
Key Takeaways:
- A first-of-its-kind study. This was an early, exploratory 3-month study — the first to look specifically at a THC:CBD medicine for restless legs syndrome.
- Signs of benefit. On average, participants’ restless legs symptoms improved, and they spent less time awake after falling asleep.
- Generally well tolerated. Side effects were mostly mild, and no serious side effects were reported.
- Early evidence only. The study was small (18 people), had no comparison group, and mostly involved people who also had multiple sclerosis. The findings point to a possible new avenue for research rather than a proven treatment.
What is Restless Leg Syndrome?
Restless legs syndrome (RLS) is a neurological condition. It causes a strong, hard-to-resist urge to move the legs, often with an uncomfortable sensation. Symptoms tend to appear when you are resting and are usually worse in the evening and at night.
This night-time pattern is thought to be linked to the body’s daily rhythm, along with changes in dopamine (a brain chemical that helps control movement) and in iron levels. Both play a part in how nerves send signals.
Restless legs and multiple sclerosis
RLS is more common in people with multiple sclerosis (MS), with estimates ranging widely from around 13% to 65%. Researchers describe two patterns in this group: a form that appears in more advanced MS, and a form that starts before MS and often runs in families.
How is restless legs syndrome usually treated?
For many years, treatment focused on medicines that boost dopamine, called dopamine agonists. More recently, UK and international guidelines have moved towards other medicines, such as gabapentin and pregabalin, as a first choice. This is partly because dopamine medicines can cause symptoms to worsen over time. Other medicines are sometimes used as well. Even so, a proportion of people do not get enough relief from any of these options, which is why researchers keep looking for alternatives.
Why are researchers looking at cannabis compounds for RLS?
Cannabis-based medicines are being studied for a range of conditions. One medicine — a mouth spray containing THC and CBD (2.7 mg THC and 2.5 mg CBD in each spray) — is licensed in the UK, but only as an add-on treatment for muscle stiffness (spasticity) in multiple sclerosis. It is not licensed to treat restless legs syndrome.
Laboratory research suggests cannabis compounds can influence chemical signals in a part of the brain involved in movement, which is one reason scientists wonder whether they might affect RLS. However, no research had tested a combined THC and CBD medicine specifically for restless legs. To address this gap in the literature, researchers conducted an exploratory, prospective, 3-month open-label trial to evaluate the efficacy and tolerability of such a medication.
What did the study involve?
This was an exploratory, open-label study that followed patients for three months. “Open-label” means everyone knew they were taking the medicine and there was no dummy (placebo) treatment for comparison. That is an important limitation of the study.
The researchers included adults with long-standing restless legs syndrome whose symptoms had not responded to current treatment. Most also had multiple sclerosis. Participants started the THC:CBD spray at the first visit, taking it in the evening before symptoms usually began. The dose was adjusted for each person over the first month to find the amount that worked best, then kept steady for the rest of the study.
To track changes, the team used validated questionnaires and wrist-worn sleep monitors (actigraphy). The main measure was restless legs severity, scored using the International Restless Legs Syndrome rating scale. They also looked at sleep, quality of life, sleepiness and how well the treatment was tolerated.
What did the study find?
Eighteen people completed the final analysis, 16 of whom also had multiple sclerosis. Half had a family history of RLS. At the start, most had severe restless legs symptoms but only mild daytime sleepiness.
Over the three months, the researchers observed several changes:
- Symptoms eased early. Restless legs severity improved within the first month and stayed better through to three months.
- Better quality of sleep. People spent significantly less time awake after first falling asleep. Other sleep measures, such as how quickly people fell asleep, did not change much.
- A third saw a large improvement. Six of the 18 participants (about a third) had at least a 50% improvement in their restless legs score at one and three months.
- No change in some areas. Daytime sleepiness and overall quality of life did not change significantly during the study.
- Because there was no comparison group, it is not possible to say for certain how much of this improvement was due to the medicine itself.
How well was the treatment tolerated?
The spray was generally well tolerated, and no serious side effects were reported. About a third of participants (6 of 18) had mild-to-moderate side effects, including dizziness, irritability, mental confusion, and a bitter, unpleasant taste from the spray. Two people (about 1 in 9) stopped early, both because of the taste.
Two-thirds of participants (12 of 18) chose to keep taking the medicine after the study because they felt it helped. Among those who continued, restless legs symptoms remained improved a year later, with no new side effects reported.
What does this mean for people with restless legs syndrome?
This was the first study to explore a combined THC:CBD medicine for restless legs syndrome, and the early results are encouraging: symptoms improved, and the treatment was generally well tolerated. That makes it a promising direction for future research.
It is important to keep the findings in perspective, though. The study was small, had no placebo or comparison group, was not blinded, and mostly involved people who also had MS — so the results may not apply to everyone with restless legs. The study also received funding from a pharmaceutical company, and several authors declared industry links. Larger, controlled studies would be needed before any firm conclusions could be drawn. For now, these findings support further investigation rather than a change in everyday care.
Speak to a Specialist
If restless legs syndrome is affecting your sleep or daily life, the first step is a conversation with your GP or a qualified specialist, who can review your symptoms and explain the treatment options that may be right for you.
If you would like to learn more about how medical cannabis is assessed and prescribed in the UK, you can complete our free online eligibility check to find out whether a consultation with one of our specialists could be a suitable next step.
