Last updated: October 2026
Muscle twitching (fasciculations) is very common and almost always harmless. Small, flickering twitches in an eyelid, calf, thigh or arm are usually set off by stress and anxiety, caffeine, hard exercise or tiredness, and they often settle within days or weeks. See a GP if a twitch lasts over 2 weeks, appears in several places, or comes with weakness.
Below: common causes, a “clue, likely cause, what to do” table, the anxiety loop, benign fasciculation syndrome, what helps and the red flags.
Quick check: twitching on its own, with normal strength, is very rarely a sign of anything serious. The thing doctors look for is weakness: struggling to grip, tripping, a foot that drags, or muscles getting visibly thinner. If your strength is normal, the most likely culprits are stress, caffeine, a hard workout or a run of poor sleep.
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.
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
| Clue | Likely cause | What to do |
|---|---|---|
| Twitching during a stressful patch; racing thoughts, tight chest, on edge | Stress or anxiety | Slow breathing, movement, tackling the cause; talking therapy if it’s ongoing |
| Worse on heavy coffee or energy drink days | Caffeine | Cut down gradually; none after early afternoon |
| Calves or feet flicker after a run or leg day | Exercise | Rest, fluids, gentle stretching; usually gone within a day or two |
| After several short or broken nights | Tiredness | Regular sleep and wake times |
| Started after a new medicine or dose change | A medicine | Check the leaflet; speak to your GP or pharmacist; don’t stop it yourself |
| Long-term twitching in several places, sometimes cramps, strength normal | Benign fasciculation syndrome | See a GP to confirm; reassurance and managing anxiety help most |
| Twitching with weight loss, fast heartbeat, feeling hot | Overactive thyroid | See a GP for a blood test |
| Twitching with tingling, cramps, long-term stomach acid tablets or diuretics | Low magnesium or calcium (uncommon) | See a GP for a blood test; don’t guess with high-dose supplements |
| Twitching with weakness, muscle wasting, slurred speech or trouble swallowing | Needs checking | See a GP promptly |
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:
- Rest and sleep. Aim for regular sleep and wake times.
- Cut back on caffeine, slowly rather than all at once to avoid headaches. See how long caffeine lasts and caffeine withdrawal.
- Drink less alcohol and find ways to relax that work for you.
- Stretch gently. The NHS suggests stretching and massaging any muscles affected by cramps. A calf stretch before bed is simple.
- Keep moving. Don’t stop exercising because of twitching; just ease off if a hard session clearly sets it off.
- 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
The 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
See 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
Your 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.
Call 999 if: weakness, a drooping face or slurred speech comes on suddenly (possible stroke), or someone has a seizure for the first time or can’t breathe properly.
FAQs
Is muscle twitching normal?
Yes. Most people get twitches from time to time, and the NHS says they are very rarely a sign of anything serious. Stress, caffeine, tiredness and exercise are the usual triggers.
Can anxiety cause muscle twitching all over the body?
Yes. Anxiety is one of the most common causes, and worrying about a twitch can make it worse. Twitches that move around the body with normal strength are typical of stress and benign fasciculation syndrome.
Is muscle twitching a sign of MND?
Very rarely. MND mainly causes muscle weakness that gets worse over time. In a study of 121 people with benign twitching followed for up to 32 years, none developed MND. See a GP if you notice weakness.
How long does muscle twitching last?
The NHS says a twitch normally stops in a few days or weeks. Benign fasciculation syndrome can come and go for months or years, but it often improves and doesn’t lead to weakness.
Can low magnesium cause muscle twitching?
It can, but it is uncommon in healthy people who eat a varied diet. Long-term stomach acid tablets or diuretics can lower magnesium. A GP blood test is the way to check.
How do I stop muscle twitching?
Get more rest, cut back on caffeine and alcohol, find ways to relax and stretch any tight muscles. There isn’t usually any treatment, and most twitches stop on their own.
When should I worry about muscle twitching?
See a GP if a twitch lasts over 2 weeks, is in more than one place, or comes with weakness, stiffness, muscle wasting, slurred speech or trouble swallowing.
Sources
- NHS. Twitching eyes and muscles.
- NHS. Motor neurone disease: symptoms.
- NHS. Health anxiety.
- NHS. Overactive thyroid: symptoms, hypoparathyroidism and vitamins and minerals: magnesium.
- NHS Scotland Right Decisions. Muscle twitches and cramps (GP factsheet).
- MHRA. Proton pump inhibitors in long-term use: reports of hypomagnesaemia.
- Blexrud MD et al (1993). Long-term follow-up of 121 patients with benign fasciculations. Annals of Neurology.
- Mattiuzzi C, Lippi G (2025). Clinical progression of benign fasciculation syndrome: a systematic literature review. Neurological Sciences.
- Montalvo A et al (2021). Benign fasciculations: a follow-up study with electrophysiological studies. Muscle and Nerve.
- Fermont J et al (2010). Prevalence and distribution of fasciculations in healthy adults: effect of age, caffeine consumption and exercise. Amyotrophic Lateral Sclerosis.
- Blackman G et al (2019). The association between benign fasciculations and health anxiety: a report of two cases and a systematic review of the literature. Psychosomatics.
- Simon NG, Kiernan MC (2013). Fasciculation anxiety syndrome in clinicians. Journal of Neurology.
- Garrison SR et al (2020). Magnesium for skeletal muscle cramps. Cochrane Database of Systematic Reviews.
This guide is general information, not medical advice. Evopure makes the Magnesium Glycinate Sleep Complex.
