Muscle Twitching: Common Causes, Anxiety and When to See a GP (UK)

What is muscle twitching?

A twitch, or fasciculation, is a small group of muscle fibres firing on their own. You might see or feel a flicker or ripple under the skin. It isn’t painful and doesn’t move the limb.

Thinking about calcium as well? Our guide to calcium supplements explains who may need one and how much is too much.

It is far more common than most people think. An NHS Scotland factsheet for GPs notes that in one study more than half of people had muscle twitching, and 37% had cramps, within a single year. When Dutch researchers scanned the muscles of 58 healthy adults with ultrasound, 43% had twitches, most often in the foot and lower leg.

Twitching is different from a cramp (a painful, hard tightening), a tremor (rhythmic shaking, see shaky hands) and hypnic jerks (the whole-body jolt as you drift off).

Common harmless causes of muscle twitching

The NHS says most twitches are not caused by a medical condition. The usual triggers are:

• Stress and anxiety. The NHS lists stress and anxiety first among the common causes. When you’re anxious you also notice body sensations more, so small twitches feel bigger. See stress symptoms.
• Caffeine. Coffee, tea, cola and energy drinks can all add to it. In a study of doctors worried about their own twitching, caffeine, stress, tiredness and exercise were the common things that made it worse.
• Exercise. In the Dutch study, strenuous exercise caused a temporary rise in twitching, but only in the lower legs.
• Tiredness and poor sleep. The NHS names tiredness and exhaustion as a common cause. See sleep debt.
• Dehydration and heavy sweating. GP guidance links dehydration with cramps rather than twitches, but cramps and twitching can go together.
• Some medicines. Check the leaflet. GP guidance mentions diuretics (water tablets) and stimulants such as methylphenidate, and the MHRA warns that a proton pump inhibitor (stomach acid medicine) taken for over a year can occasionally lower magnesium. Don’t stop a prescribed medicine without advice.
• Low magnesium or calcium. Possible, but honestly uncommon in well people. The NHS says a varied diet should give you all the magnesium you need, and low calcium is usually linked to a specific problem such as the parathyroid glands not working properly (often after neck surgery, the NHS says). See signs of magnesium deficiency.
• An overactive thyroid. The NHS lists twitching or trembling among the symptoms, with weight loss, a fast heartbeat and nervous energy.

Muscle twitching: clue, likely cause, what to do

Anxiety and muscle twitching: the worry loop

Anxiety and twitching feed each other. A twitch appears, you search it online, you read about motor neurone disease (MND, also called ALS), and the fear keeps you on high alert. Worry, poor sleep and extra coffee make the twitching worse, which feels like proof that something is wrong.

Doctors know this pattern well. The NHS Scotland GP factsheet says health anxiety, specifically about MND, can amplify twitching, and that it is especially common in health professionals. A King’s College London review of 8 studies (384 people) found anxiety often went hand in hand with benign twitching, and that the worry was overwhelmingly about MND. The authors suggested the link may run both ways, and that cognitive behavioural therapy (CBT) can help.

In a small Australian study of 20 doctors with twitching, 14 had normal strength and normal nerve tests, with worry driving the symptoms. The few who did have a nerve problem also had weakness or numbness, not twitching alone.

If this sounds like you, a few things help:

• Notice the checking. The NHS suggests noting how often you check your body or look up symptoms, then cutting back gradually.
• Calm the body. Slow breathing such as box breathing can take the edge off. See how to calm down.
• Get proper help if it’s taking over. See health anxiety and anxiety symptoms. Adults in England can refer themselves to NHS Talking Therapies.

Benign fasciculation syndrome (and why it isn’t MND)

Benign fasciculation syndrome (BFS) is the name for long-lasting twitching, often with cramps, in someone whose strength, nerve tests and examination are normal. The NHS describes it as twitches and cramps caused by overactive nerves.

The follow-up research is reassuring:

• A Mayo Clinic study followed 121 people with benign fasciculations for 2 to 32 years. None developed MND.
• A 2025 review of three studies (180 people) found no one developed motor neurone problems at follow-up. Twitching persisted in 98% but improved in about half.
• A Lisbon study followed people for a median of 4.7 years. Two-thirds reported their symptoms had improved.

So BFS can linger, but it is benign. The key difference from MND is weakness. The NHS describes MND as uncommon, usually affecting people over 50, and causing muscle weakness that gets worse over months or years, such as trouble gripping or climbing stairs.

Where people notice twitching

• Eyelid. The most familiar twitch, nearly always benign and usually linked to tiredness, stress and caffeine. See our guide to eye twitching.
• Calf and foot. The NHS says twitches in the legs are particularly common, and GP guidance notes they are most often felt in the calves, especially after exercise.
• Thigh. Also common in benign twitching. In the Lisbon study, most people with BFS had twitches in both arms and legs.
• Arm and hand. Usually benign too. GP guidance notes that painless, repetitive twitching (myokymia) is commonly seen around the eye or in the hand muscle between the thumb and index finger.
• All over the body. Twitches that jump from place to place are typical of stress, poor sleep and BFS. Twitching in more than one place is still a reason to see a GP, so they can check your strength.

How to stop muscle twitching

The NHS says there isn’t usually any treatment for twitching, and it normally stops in a few days or weeks. These steps tackle the triggers:

1. Rest and sleep. Aim for regular sleep and wake times.
2. Cut back on caffeine, slowly rather than all at once to avoid headaches. See how long caffeine lasts and caffeine withdrawal.
3. Drink less alcohol and find ways to relax that work for you.
4. Stretch gently. The NHS suggests stretching and massaging any muscles affected by cramps. A calf stretch before bed is simple.
5. Keep moving. Don’t stop exercising because of twitching; just ease off if a hard session clearly sets it off.
6. Try not to worry. The NHS points out that worrying can make a twitch worse.

What about magnesium? Magnesium supplements are not a proven fix for twitching. A Cochrane review found magnesium unlikely to prevent typical muscle cramps in older adults. If you think you might be low, ask your GP for a blood test rather than guessing. See magnesium for cramps and magnesium for restless legs.

If you’d like a caffeine-free drink as part of an evening wind-down, our Magnesium Glycinate Sleep Complex is a berry-flavoured powder made with magnesium bisglycinate and citrate. Magnesium contributes to normal muscle function and to normal functioning of the nervous system. It isn’t a treatment for twitching, and most people who twitch don’t need a supplement.

When to see a GP about muscle twitching

iThe NHS says to see a GP if:

• a twitch lasts more than 2 weeks
• you have twitches in more than 1 place
• the affected area feels weak or stiff
• you think a prescribed medicine might be causing it

iSee a GP promptly if twitching comes with any of these:

• muscle weakness, such as dropping things, struggling to grip or climb stairs, or tripping
• muscles that look thinner or wasted
• slurred speech or trouble swallowing
• cramps that keep getting worse
• numbness, or tingling that doesn’t go away

iYour GP will ask about your symptoms, examine you, and may arrange blood tests. GP guidance suggests checking salts (electrolytes), calcium and thyroid function. If anything is unclear, they can refer you to a neurologist. Most people are reassured at this stage.

Twitching or trembling can also be a sign of an overactive thyroid.

An urge to move your legs in the evening is different from twitching; see restless legs vs cramps, twitches and jerks.

Twitching with bone pain or muscle weakness can be a sign of very low vitamin D; see severe vitamin D deficiency symptoms.