Muscle twitches are very common, and the NHS says they are very rarely a sign of anything serious. They are often linked to stress and anxiety, tiredness, caffeine or alcohol, and some medicines. They are also common after exercise, especially in the calves. Most twitches settle on their own within a few days or weeks.
The worry many people have is motor neurone disease (MND). The key point is weakness. MND causes muscle weakness that gets worse over time. Twitching on its own, with normal strength, is a different picture. Studies that followed people with harmless twitching for years found that none of them developed MND. This guide explains the common causes, the features worth getting checked, and what a GP will do.
Twitching by itself is not an emergency. Call 112 or 999 (Ireland), 999 (UK) or 911 (US) if:
See a GP (not urgent) if:
A twitch is a small, involuntary flicker in a muscle that you can see or feel under the skin. Doctors call the most common kind a fasciculation. Twitching around the eye is often a slightly different type, called myokymia. A guidance sheet for GPs from NHS Scotland's neurology service describes both as nearly always benign.
How common is it? In one small study, researchers used ultrasound to look for twitches in the muscles of 58 healthy adults. They found them in 25 people (43%), mostly in a muscle of the foot. Twitches were rare above the knee, and people with twitches tended to be older.
The NHS lists stress and anxiety first among the things twitches are linked to. It also says worrying about a twitch can make it worse. The Scottish GP guidance makes the same point: anxiety about MND in particular can amplify twitching.
The NHS links twitches to tiredness and exhaustion, and advises getting plenty of rest. Our guide to how much sleep adults need covers what "enough" looks like.
The NHS links twitches to caffeine and alcohol, and suggests not drinking lots of either. The research picture is mixed. In the ultrasound study above, people's usual caffeine intake made no difference to whether twitches were found. That was a small study of 58 people, so it does not rule caffeine out. Cutting back is a reasonable experiment if you drink a lot.
The Scottish GP guidance says twitches are most common in the calves and after exercise. In the same study, regular exercise made no difference to twitching. But in a small test with 10 healthy adults, hard exercise caused a temporary increase in twitches, only in the lower leg muscles.
The NHS says some medicines can cause twitches, and suggests checking the leaflet. The Scottish guidance mentions medicines such as diuretics ("water tablets") and methylphenidate, a stimulant used for ADHD. These can upset the balance of salts and minerals in the blood, called electrolytes. The NHS advises not stopping a prescribed medicine without medical advice, even if you think it is causing your twitch.
Some people have twitching that keeps going for months, often with cramps. The NHS calls this benign fasciculation syndrome: long-lasting twitches and cramps caused by overactive nerves. "Benign" means harmless. The Scottish guidance says a family history is common.
The research here is reassuring about MND, but honest about the twitching itself:
So the twitching often lasts, even though it is harmless. NHS Scotland's guidance says most people are reassured by a careful explanation. The 2025 review notes that MND starting after this kind of twitching has been described only in individual case reports.
These were small studies of people seen at specialist clinics. In the Mayo study, everyone had a normal examination and nerve tests at the start, apart from the twitches. That is the point: the reassurance applies to twitching without weakness, after a doctor has checked you.
The NHS describes MND as an uncommon condition that causes weakness that gets worse over time. It usually affects people over 50, though adults of any age can get it.
Early MND symptoms listed by the NHS include:
The NHS notes that early twitches and weakness can look like less serious conditions, which is why they should be checked. The Scottish GP guidance says twitching without weakness is usually benign. It advises referral to neurology for any wasting or weakness, very widespread twitching, or twitching with severe cramps.
If you can grip, climb stairs and walk normally, twitching alone points strongly away from MND. If you have noticed real weakness, see your GP.
Shaking is different from twitching. A rhythmic tremor in the hands is covered in our piece on essential tremor and Parkinson's.
The Scottish GP guidance suggests questions such as:
Expect a short examination of strength and reflexes. The guidance suggests blood tests for:
The NHS says a GP may also ask you to come back if the twitch has not stopped in a few weeks. If there are other symptoms, they may refer you to a neurologist. For suspected MND, the NHS says tests can include blood tests, tests of how well the nerves are working, and an MRI scan.
Twitching and health anxiety can feed each other. The NHS describes health anxiety as worrying about being ill so much that it takes over your life. Signs include checking your body, seeking reassurance and searching online.
The Scottish guidance notes that health anxiety about twitching is especially common in health professionals. In the Mayo Clinic study, 40 of the 121 people worked in healthcare. The guidance advises a clear explanation for health anxiety, and avoiding repeated reassurance.
Not everyone with twitching is anxious, though. In the two-year study most people said they felt anxious, but only 14% scored as anxious on a standard questionnaire.
The NHS suggests self-help such as keeping a diary of checking, challenging worried thoughts and gradually returning to things you have avoided. See a GP if worry is stopping you living normally. A GP may refer you for talking therapy such as CBT. Our guides to anxiety as a feeling versus a disorder and what actually works for anxiety go further.
If you are struggling to cope, you can talk to Samaritans any time, free, on 116 123 in Ireland and the UK. In Ireland you can also text 50808. In the US, call or text 988.
The NHS suggests:
Rarely. The NHS says twitches in the eyes are particularly common. Painless twitching around the eye is usually myokymia, which the Scottish guidance describes as nearly always benign. See a GP if it lasts more than 2 weeks or you have twitches in more than one place.
The NHS links twitches to stress and anxiety, and says worry can make them worse. But twitching also happens in people who are not anxious, so it is not "all in your head".
Often not completely. In the follow-up studies, twitching persisted in most people, though it improved in about half. Importantly, no one in those studies went on to develop MND.
Not on its own. Widespread twitching is one reason the Scottish guidance suggests a neurology opinion, so see your GP. What matters most is whether there is weakness or muscle wasting. Many people with widespread benign twitching have normal strength.
This article is general information, not medical advice. It cannot tell you the cause of your symptoms. If a twitch lasts more than 2 weeks, or you notice weakness, see your GP.
Reviewed by: Proco Team
Last updated: November 2026