Cannabinoids May Ease Multiple Sclerosis-Related Spasticity
Muscle cramps and neurological spasticity are different problems, and cannabis-based treatments have not been studied equally for both. A brief cramp after exercise may result from fatigue, dehydration, overuse, heat, or an awkward stretch. Rest, gentle stretching, massage, and rehydration often help. Persistent or severe spasms, however, may be linked to conditions such as multiple sclerosis (MS), spinal-cord injury, stroke, or medication effects and should be evaluated by a health professional.
The strongest evidence for cannabis-based medicines concerns spasticity associated with MS—not routine exercise-related muscle cramps and not general muscle recovery. These products typically contain varying amounts of tetrahydrocannabinol (THC), cannabidiol (CBD), or both. THC is intoxicating, while CBD is not generally intoxicating, although both can affect the brain and interact with other medicines.
One frequently cited study from the University of South Carolina examined a 1:1 THC-CBD combination in mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. In the published study, treatment reduced signs of paralysis and altered inflammatory immune responses and gut-microbiome patterns. These results provide a possible explanation for how cannabinoids might influence neuroinflammation, but they do not demonstrate that the same treatment will prevent inflammation or improve muscle function in people. Animal findings should not be presented as proof of a clinical treatment.
Human research has produced more relevant, though still limited, evidence. In a small cross-sectional survey at the University of Rochester MS Center, 14 patients with MS or transverse myelitis reported their experiences with medical marijuana. Of the participants who used it, 77% said it helped primarily with spasticity and pain, while 70% reported an improved quality of life. Because the study relied on self-reports, had a very small sample, and did not randomly assign treatment or use a placebo group, it cannot establish that cannabis caused those improvements. The results are best viewed as preliminary real-world observations. The conference study abstract also reported that some participants reduced other symptom medications, but that finding requires confirmation in controlled trials.
Better-quality trials suggest that specific cannabis-based medicines—particularly THC-CBD products such as nabiximols—can modestly improve patient-reported spasticity in some people with MS. A 2022 Cochrane review concluded that nabiximols probably reduces short-term spasticity severity compared with placebo, while emphasizing that the overall evidence is limited and that side effects may lead some people to stop treatment. Benefits have generally been clearer for how patients feel than for objective measurements of muscle tone or neurological function.
That distinction matters. Evidence that a cannabinoid medicine may relieve MS-related stiffness, painful spasms, or sleep disruption does not show that CBD or cannabis accelerates muscle repair after exercise. Claims that cannabis reliably reduces workout-related inflammation or improves muscle growth and recovery are not established by the studies described above.
Cannabis-based medicines can also cause adverse effects, including dizziness, sleepiness, impaired attention, balance problems, dry mouth, nausea, and cognitive changes. CBD is not automatically risk-free: the U.S. Food and Drug Administration notes potential liver injury and drug interactions, and over-the-counter products may contain inaccurate amounts of CBD, THC, or contaminants. THC-CBD products may also intensify sedation and other drug effects depending on the dose and route of administration.
For someone with MS-related spasticity who has not obtained enough relief from standard treatments, a clinician may consider a regulated cannabinoid medicine as an adjunct—not a replacement—for established care. Anyone considering cannabis or CBD should discuss the product, dose, other medications, liver health, fall risk, and possible impairment with a qualified healthcare professional. New, severe, or recurring spasms should be assessed for an underlying medical condition rather than treated solely with an over-the-counter cannabis product.
