The involuntary contraction of muscles that occur when your knee twitches, are usually caused by the muscles in your thigh, rather than the knee itself. The occasional twitch of your knee (or any body part) is normal. Frequent twitching on the other hand, can have a number of causes.

These spasms and twitches are typically the result of muscle fatigue or strain. However, sometimes muscle twitching can be a sign of an underlying medical problem.

Beyond muscle fatigue and strain, here are some causes of knee twitching:

Dehydration

Many people don’t drink enough water per day. But dehydration can be serious if left long term and can deplete levels of:

These low levels can result in muscle twitching.

Treatment: Stay hydrated, especially when exercising. Aim to drink water throughout the day.

Vitamin deficiencies

Muscle twitching can also be the result of a lack of nutrients in your diet. Key nutrients you should be sure to get include:

Treatment: If you’re unsure, have your doctor take a blood test to check your levels. Then, make dietary changes or take supplements as needed. You can also get vitamin D from the sun!

Drug side effects

Some people experience muscle spasms and twitching as a side effect from taking certain drugs. Medications that can cause muscle spasms include:

Treatment: Work with your doctor to adjust your dosage or change to an alternative medication if the twitching is becoming bothersome.

Stimulant overdose

Did you know you can overdose on caffeine? You can. And overdosing on things like caffeine, amphetamines, or other stimulants can cause muscle twitching and spasms.

Treatment: If you suspect a serious overdose, seek immediate emergency medical attention. If you’ve been taking a lot of stimulants or drinking a lot of caffeinated beverages and have noticed muscle twitching, reduce your intake and see if the twitching subsides.

Amyotrophic lateral sclerosis (ALS)

Muscle twitching and cramps can be an early sign of ALS, also known as Lou Gehrig’s disease. This is a degenerative disorder that affects the brain and spinal cord.

Treatment: There’s currently no cure for ALS, but the progression of symptoms can be controlled. Your doctor may suggest a combination of physical and occupational therapy along with medications such as:

An autoimmune disorder

Some autoimmune disorders — such as neuromyotonia (Isaac syndrome) — can have symptoms that include muscle twitches and spasms.

Treatment: Your doctor will typically prescribe anti-seizure medications, like gabapentin (Neurontin, Gralise).

Although it will depend on the diagnosis, most doctors will start treating frequent muscle twitching by recommending nonmedical, lifestyle changes. These changes include:

If your twitching is related to stimulants or caffeine, you’ll need to monitor your intake. You’ll also need to ensure you’re getting proper nutrition if a deficiency is the root cause of your knee twitching.

If medication is warranted, your doctor will monitor the side effects. In most cases, treatment is individualized to the specific condition.

If you’ve ruled out muscle fatigue or strain as the cause of your knee twitching, make an appointment with your doctor. They can evaluate you to see if you need further testing for deficiencies or other health conditions.

See your doctor as soon as possible if your twitching or spasms are accompanied by:

Chances are that an occasional knee twitch is just a response to fatigue or strain of your thigh muscles. Twitches and spasms, however, could be the symptoms of a condition that requires medical attention.

If your knee continues to twitch, monitor it and keep an eye out for other symptoms that will be helpful for your next visit with your doctor.