Individuals may experience weakness for different reasons. For people with MS, demyelination interrupts the flow of nerve impulses in the spinal cord or (less frequently) in the brain that keep a muscle or group of muscles functioning properly. As a result, muscles lose strength.

Other symptoms of MS and their treatments can also be involved with weakness. For instance, if taking too much medication for spasticity (muscle tightness), it can have the opposite effect by increasing weakness. A doctor should also test for other conditions that can cause weakness, such as diabetes, infection, or depression.

Managing Weakness

Updated in May 2024 by Dr. Barry Hendin, MSAA Chief Medical Officer
Original content by Randall T. Schapiro, MD

Schapiro, R. T., Managing the Symptoms of Multiple Sclerosis, 5th edition, (Demos Medical Publishing, 2007)

Go to Introduction to Multiple Sclerosis Symptom Management

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