Twitching eyes and muscles
A twitch is a brief involuntary contraction of a small bundle of muscle fibres. It feels like a flutter or a wave running under the skin, but the joint does…
Prescription review online
A doctor will review your case and issue a prescription if medically appropriate.
Talk to a doctor online
Discuss your symptoms and possible next steps with a doctor online.
On this page
A twitch is a brief involuntary contraction of a small bundle of muscle fibres. It feels like a flutter or a wave running under the skin, but the joint does not move: the finger does not bend, the eye does not close. The eyelid, the calf and the thigh twitch most often, the shoulder or the muscles around the mouth less so.
Almost everybody gets this, and in the overwhelming majority of cases there is no illness behind it. That is exactly what makes the subject awkward: reassurance is needed here more than alarm, and yet there is one combination of signs worth reading to the end for.
Why a muscle twitches on its own
The nerve ending that governs a small group of fibres sometimes fires without any instruction. That spontaneous discharge is called a fasciculation, and it occurs in healthy people — studies find it in nearly everybody if you watch for long enough.
Its likelihood rises noticeably with:
- lack of sleep and exhaustion;
- caffeine — coffee, tea, energy drinks, pre-workout supplements;
- stress and anxiety, and the ordinary strain of a long working day;
- hard physical effort, especially if you are not used to it: calves twitch in the evening after a long walk or a training session;
- dehydration and salt lost in sweat;
- alcohol and nicotine.
A twitch is worth distinguishing from a cramp: a twitch does not hurt and does not change the position of the limb, while a cramp is a painful squeezing of the whole muscle that locks the leg. In one and the same person the two often go together and for the same reasons, but they are different things.
When the eyelid twitches
The commonest version is eyelid myokymia. Usually the lower lid of one eye flickers, in bouts lasting seconds or minutes, and it can come back many times a day over several days or weeks. From the outside it is often barely visible, even though the person is convinced everyone can see it.
Its causes are the ones listed above, plus a few to do with the eye itself:
- dry eye — from air conditioning, wind, contact lenses or long spells at a screen, when people blink less often;
- eye strain and glasses that no longer match: if your sight has not been checked for a while, here is a reason to do it;
- irritation of the lid margin from mild inflammation.
Eyelid myokymia settles on its own and needs no treatment. Simple things help: several nights of proper sleep, less coffee, breaks away from the screen, lubricating drops, a warm compress. It is worth seeing a doctor if the flickering lasts more than a few weeks, spreads from the lid to other muscles of the face, or if the eye is also red, painful and seeing less well.
Twitching in the muscles of the body
In the arms and legs twitches look like a stirring or rolling under the skin, nearly always in the same spot, though they sometimes "jump" from one muscle to another. Some people notice them only in bed at night, because during the day their attention is elsewhere.
If they carry on for months, no strength is lost in the limbs, the muscles do not shrink and tests find nothing abnormal, this is what is called benign fasciculation syndrome. The name is clumsy but the meaning matters: it is not the beginning of a disease nor an early stage of anything, it is a condition in its own right and a harmless one. It is a nuisance and it can go on for years, but it does not lead to weakness.
There is also a very common story alongside it: the anxiety that grows around the twitching. A person reads about rare diseases, starts watching their legs for movement, finds it more often, worries more, sleeps worse — and the twitching increases. That circle is broken not by monitoring the muscles but by an examination that removes the uncertainty.
What marks out the dangerous kind
Twitches in themselves, even frequent ones going back years, carry no alarm value. The value lies in what comes with them.
You need to reach a neurologist if the twitching goes together with any of the following:
- increasing weakness: things start dropping out of your hands, turning a key or opening a jar is hard, getting up from a chair and climbing stairs is heavy going, a foot begins to catch on the floor;
- a muscle visibly wasting — the space between thumb and index finger becomes hollow, the shoulder or the calf thins down, and often you can see it by comparing with the other side;
- speech becoming unclear or nasal, a change in the voice;
- trouble swallowing, choking on liquids, food getting stuck;
- twitching of the tongue together with a change in speech;
- difficulty breathing when lying flat.
It is precisely that combination — twitching plus weakness and loss of muscle bulk — that raises the question of motor neurone disease, an uncommon condition that is otherwise easy to miss. The proportion is what matters here: twitching without weakness happens constantly and almost never means anything, while in that disease twitching is almost never the first and only symptom. A calf that has been twitching for years with full strength in the legs is therefore an argument against such a diagnosis, not for it.
Persistent twitching with weakness or numbness also has far commoner causes: a compressed nerve root in the spine, entrapment syndromes, the after-effects of an injury to a nerve. A neurologist finds those too, and they can be treated.
When the eye closes against your will
This is no longer eyelid flickering but a different phenomenon, and the two get confused constantly. The difference is simple: myokymia is a fine flutter that does not stop you seeing, whereas here the muscle really does clamp shut.
Blepharospasm. Both eyes start screwing up and closing involuntarily. First it is more frequent blinking, then attacks in which the eyes will not open straight away. Bright light, wind, reading, driving and nerves all make the spasm worse. In severe cases a person can barely use their sight even though the eyes themselves are healthy.
Hemifacial spasm. It grips one half of the face: the twitching starts around one eye and over time moves down to the cheek and the corner of the mouth, so that half the face is pulled out of shape. The usual cause is a blood vessel lying against the facial nerve where it leaves the brain and irritating it; a magnetic resonance scan is used to sort this out.
The main point about both: they are treatable. The mainstay is injections of botulinum toxin into the relevant muscles, repeated every few months, and it usually works well; in hemifacial spasm an operation that separates the nerve from the vessel is sometimes considered. It is not worth waiting for these to pass by themselves the way eyelid flickering does — they do not.
Tics
A tic differs from a fasciculation in being a whole movement: a blink, screwing up the eyes, a jerk of the head or shoulder, a sniff, a throat-clearing, a short sound. There is often an inner sense beforehand that it "has to be done", and it can be held back briefly by an effort of will, after which it returns more strongly.
In children tics are common and usually clear up on their own within a few months. Tiredness, excitement, illness and other people's attention all make them worse, so the most useful thing a parent can do is not to correct the child or ask them to stop: comments increase tics rather than removing them. A doctor is worth seeing if the tics interfere with school and with other children, if they last more than a year, or if involuntary sounds and words join the movements.
In adults a tic starting for the first time is far less usual and is worth showing to a doctor, particularly if it appeared while taking a medicine.
Medicines, salts and the magnesium myth
Twitching can be a side effect of medicines. The commonest culprits are the inhalers that open the airways, products containing caffeine and stimulants, some antidepressants, thyroid hormone at an excessive dose, and diuretics, the last of these through loss of salts. Separately there are the medicines used in psychiatry: they cause not fasciculations but other involuntary movements, for instance around the mouth and tongue. Tell a doctor about that promptly, without stopping the treatment on your own.
Now for magnesium, which this whole subject is habitually explained by. A genuine magnesium deficiency does cause twitching, but it is uncommon and turns up almost always in recognisable circumstances: prolonged diarrhoea or bowel disease, alcohol dependence, years of diuretics or of medicines that reduce stomach acid, kidney disease. And it does not arrive alone — weakness, cramps, palpitations and numbness around the mouth come with it, because calcium and potassium fall in company.
Taking magnesium "just in case", without any blood tests, is therefore not a good idea. It will do nothing for a healthy person with a flickering eyelid, because that is not the cause; in kidney disease magnesium supplements can be unsafe; and at high doses it simply causes diarrhoea. The sensible order is the reverse: if the twitching is persistent, a doctor will arrange a blood test including magnesium, calcium, potassium, glucose and thyroid hormones, and the decision about supplements will rest on the result.
What happens at the appointment
Usually the examination is enough. The doctor will look at exactly where the twitching is, test strength in the arms and legs, the reflexes and sensation, compare muscle bulk on the two sides, assess speech and swallowing, and inspect the tongue. They will ask how long it has been going on, whether it is always in the same place, what makes it worse, how much you sleep and how much coffee you drink, and what medicines you take.
If strength is intact, the muscles are unchanged and the twitching is the only complaint, the work-up usually ends there: a blood test and a follow-up appointment in a few weeks to confirm that nothing has been added. Nerve conduction studies and electromyography, which measure the electrical activity of muscles and nerves, and sometimes a scan, are arranged when the examination has found weakness or other abnormal signs. It is the examination that decides.
Ordinary twitching has no treatment because there is nothing to treat. What works is sleep, less caffeine, sensible exercise, stretching and massaging the muscles prone to cramp, and taking away the anxiety around the symptom itself. If a cause is found — a medicine, the thyroid, a shortage of salts, blepharospasm — that cause is treated.
Online consultation
An online appointment is a good way to work out which of the situations above yours belongs to, instead of guessing for weeks. The doctor will ask what exactly is happening, ask you to show the spot and, if you can, to film a short video: a recording shows the difference clearly between a fine flutter of the lid, a forced closing of the eye and a tic, whereas in the consulting room a twitch often "hides".
After the conversation the doctor will say whether tests are needed and which ones, go through the list of your medicines, explain what should put you on alert, and warn you specifically if the signs call for a neurologist rather than watching and waiting. What an online consultation cannot do is replace a neurological examination, but most of the time it saves both anxiety and unnecessary tests.
This material is for information only and does not replace medical advice.
Consult with a doctor about Twitching eyes and muscles
Discuss your symptoms and possible next steps with a doctor online.
Online doctors for Twitching eyes and muscles
Discuss your symptoms and possible next steps for Twitching eyes and muscles with a doctor online.
