What are the common causes of muscle weakness in the legs?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Leg muscle weakness can stem from a range of health conditions, including nerve disorders (such as neuropathy, sciatica, or multiple sclerosis), muscle diseases (like muscular dystrophy or myositis), circulation problems, electrolyte imbalances, or spinal issues. Because the underlying causes vary widely in severity, identifying the source of your symptoms is essential for getting the right treatment.

Rather than waiting and wondering, you can take a free, instant, online symptom check to help clarify what may be behind your leg weakness. In just a few minutes, you'll gain personalized insights into possible causes and clear guidance on next steps—empowering you to have a more informed conversation with your healthcare provider.

Reviewed for medical accuracy: 07/14/2026

Important Next Steps

Learn what’s causing your leg weakness Find out if leg weakness is serious Discover likely causes of weak legs See OTC options for leg weakness Find a doctor for leg weakness Understand safe home remedies for leg weakness Check symptoms behind sudden leg weakness

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Explanation

Muscle weakness in the legs can be caused by a wide variety of health conditions, including but not limited to nerve or muscle problems, some medications, and long-term heavy alcohol use.

Some Common Causes of Muscle Weakness In The Legs

Nerve-related: Examples of nerve-related problems that can cause leg weakness include stroke and sciatica (which affects the spinal cord). Long-term heavy alcohol use can also affect the nerves.
Muscle-related: If your muscles don't get enough exercise (including strength or resistance training), they can get weak. More information on exercise is available at https://familydoctor.org/exercise-how-to-get-started/. Long-term heavy alcohol use can also cause muscle weakness. In addition, some frequently prescribed medications can cause muscle weakness. For example, long-term, frequent use of steroid pills (like prednisone) can cause muscle weakness. Less commonly, a particular type of medicine to lower cholesterol can cause muscle weakness in certain
Other Causes: Other causes of muscle weakness in the legs include some infections, autoimmune disorders, and thyroid hormone problems.

If you are experiencing muscle weakness, you can use our free AI symptom checker to help identify potential causes before talking to a healthcare provider, who can determine the appropriate treatment. If there are any warning signs like suddenly becoming unable to walk or control when you urinate, it's critical to seek emergency medical care for these symptoms.

(References)

Riggs JE. (1985). Adult-onset muscle weakness. How to identify the .... Postgraduate medicine, 4034446.
Larson ST, & Wilbur J. (2020). Muscle Weakness in Adults: Evaluation and Differential .... American family physician, 31939642.
Schubert KM, & Schreiner B. (2023). Focus On Muscle Weakness. Praxis, 37632430.

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