Leg Weakness: Possible Causes and Related Symptoms

Medically Reviewed By Meredith Goodwin, MD, FAAFP

Leg weakness may develop in one or both legs. It can occur due to illness or fatigue but may have more serious causes. Sudden onset of muscle weakness in any part of your body, including the legs, can be a sign of stroke. This is a potentially life threatening condition in which part of the brain is deprived of oxygen.

Certain neuromuscular diseases can cause leg weakness. Toxins such as botulinum toxin (Botox) and certain medications can also cause weakness in the legs.

This article will focus on conditions that cause loss of strength in the leg muscles. It will also discuss treatment options and when to seek medical care for leg weakness.


Sudden leg weakness can be a sign of stroke, a potentially life threatening condition.

Warning signs of stroke

Seek immediate medical care (call 911) for leg weakness that occurs suddenly, particularly if it is felt on one side of the body or occurs with serious symptoms such as:

  • arm weakness
  • paralysis or inability to move any body part
  • loss of balance or coordination
  • numbness
  • facial drooping
  • difficulty speaking or understanding speech
  • loss of bladder or bowel control
  • blurred vision or double vision
  • fainting or change in consciousness
  • severe headache
  • fever higher than 101°F (38°C)

Transient ischemic attack (TIA)

A TIA may also be referred to as a “mini stroke.” It can have symptoms similar to a stroke but only last for a short time. Symptoms of a TIA can last Trusted Source American Stroke Association Highly respected international organization Go to source anywhere from a few minutes to a full day.

Even though a TIA might appear to go away on its own, it could be an early sign of a larger stroke. Call 911 for any symptoms of a TIA.


Woman on beach with bare legs on sand near ocean water
David Prado/Stocksy United

Sciatica is a common Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source type of nerve pain that can cause leg weakness. It results from compression of the sciatic nerve, the largest Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source nerve in the body. This nerve runs from the base of the spine through the buttocks and down each leg.

Other symptoms

In addition to leg weakness, symptoms of sciatica may include:

  • lower back pain, typically on one side
  • pain or burning sensation in the buttocks
  • pricking or pins-and-needles sensation
  • leg that feels “heavy”
  • reduced range of motion

Learn more about sciatica causes, risk factors, and treatments.

Spine conditions

Other conditions affecting the spinal cord, backbone (vertebrae), or nerves exiting the spinal cord can all cause leg weakness. These conditions include:

Other symptoms

Along with weakness in the legs, other symptoms that may indicate a spine condition include:

  • pain in the back that may radiate to other areas
  • burning sensation
  • numbness
  • tingling or pins-and-needles sensation
  • back pain that occurs with a fever higher than 100.4°F (38°C)
  • back pain that occurs during sleep
  • stiffness upon waking
  • pain that gets worse when lying down

If you experience leg weakness along with any of these symptoms, contact your doctor right away for an evaluation. It may be Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source an indication of a serious spine condition that requires prompt treatment.

Neuromuscular disease

Neuromuscular diseases can decrease function in muscles and nerves, including those in the legs.

Neuromuscular conditions that can have leg weakness as a symptom include:

SMA primarily affects infants and young children. According to the Muscular Dystrophy Association (MDA), an early symptom of SMA type 2 is muscle weakness in the legs. This typically presents in children ages 3 to 15 months. If your child shows any signs of muscle weakness, contact your pediatrician right away.

Other symptoms

Neuromuscular diseases can cause other symptoms along with leg weakness, including:


Certain treatments and medications may cause muscle weakness, including:

  • botulinum toxin (Botox)
  • statins
  • corticosteroids

Other symptoms

Other symptoms and side effects due to medications or exposure to toxins include:

Treatments for leg weakness

Treatment for leg weakness will focus on addressing the underlying cause of the condition.


Stroke requires emergency treatment as soon as symptoms appear. Remember to think F.A.S.T.:

Recovery after a stroke may involve a team of care professionals to help address a variety of needs.

Learn what to expect during recovery after a stroke.


Many cases of sciatica resolve Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source with home treatment in 4–6 weeks. This can include rest, hot or cold packs, and over-the-counter (OTC) pain relievers.

If symptoms of sciatica persist or worsen, your doctor may recommend medical therapies including:

  • muscle relaxants
  • prescription pain relievers
  • oral corticosteroids
  • corticosteroid injections to the affected area
  • physical therapy

If a structural issue in the spine is causing your sciatica, your doctor may discuss surgical treatment options.

Spine conditions

Similar to sciatica, initial treatment for many spine conditions focuses on non-invasive measures, including:

  • physical therapy
  • OTC pain relievers, such as nonsteroidal anti-inflammatory drugs (NSAIDs)
  • prescription pain relievers
  • muscle relaxants

Other treatments for spine conditions may include:

In severe cases, surgery may be necessary to treat the underlying cause of a spine condition. This may include laminectomy or discectomy to address compression of the nerves.

Neuromuscular disease

Treatment for neuromuscular disease can vary widely depending on the type. Your doctor will assess your specific condition and suggest treatment options that may be best for you.

According to the MDA, possible treatments for neuromuscular disease can include:

  • medications, including corticosteroids
  • speech therapy
  • physical therapy
  • breathing assistance
  • assistive devices such as standing frames, braces, and wheelchairs

You may also be able to access new treatment options by participating in clinical trials. Talk with your doctor about your eligibility for clinical trials near you.


Leg weakness may be a side effect of certain medications. If you suspect medication may be causing your leg weakness, contact your doctor. They can suggest alternative treatments that may have less challenging side effects.

Frequently asked questions

The following frequently asked questions have been reviewed by Meredith Goodwin, M.D.

Does COVID-19 cause weakness in the legs?

COVID-19 can cause weakness in the legs. An early 2022 analysis found that musculoskeletal symptoms occurred in people with mild to moderate COVID-19. Symptoms of muscle weakness can also persist in cases of long COVID, making it difficult for some to maintain daily activities.

Can a deficiency cause weakness in the legs?

A thiamine (vitamin B1) deficiency can cause a condition known as dry beriberi, which affects the central nervous system. Symptoms can include Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source loss of feeling or muscle control in the legs and feet. Deficiencies in vitamin B12 and folate can also cause numbness and weakness in legs.

Can heart problems cause weakness in the legs?

Yes. Heart failure makes it more difficult for blood to reach your legs and feet. This can result Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source in muscle weakness and fatigue. A prolonged vitamin B1 deficiency can also cause Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source cardiovascular symptoms and lead to wet beriberi. This is a medical emergency that requires immediate treatment.


Leg weakness can result from sciatica, spine conditions, neuromuscular disease, and certain medications. Sudden leg weakness may be a sign of stroke. Call 911 for any sudden muscle weakness, particularly if it occurs with facial drooping, severe headache, or slurred speech.

Treatment for leg weakness varies depending on the underlying cause. Your doctor can provide you with an accurate diagnosis and discuss treatment options that are right for you.

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Medical Reviewer: Meredith Goodwin, MD, FAAFP
Last Review Date: 2022 Sep 12
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