Reason you can’t fix your restless legs syndrome, the surprising cause… and the cheap daily supplement that could cure you. I’ve treated so many sufferers, reveals DR PHILIPPA KAYE, and this is what I’ve discovered

Molly came into the surgery absolutely exhausted, her three children trailing in behind her. 

She had been struggling to sleep for weeks – not just finding it hard to drop off but lying there night after night as her legs ached and twitched, utterly beyond her control. 

The fatigue had reached the point where it was affecting everything: her ability to work, to look after her children, even her mood. 

She had experienced restless legs before, in the final weeks of her last two pregnancies, but it had cleared up after each birth. 

This time there was no obvious explanation. She had even taken a pregnancy test. It was negative. She was at the end of her tether.

Restless legs syndrome – also known as Willis-Ekbom disease or RLS – is more common than most people realise, affecting somewhere between five and ten per cent of the population, though to varying degrees of severity. 

It is twice as common in women as in men and becomes more prevalent with age. 

It is characterised by an irresistible urge to move the legs, usually driven by deeply unpleasant sensations: a gnawing ache like toothache, an electric-shock feeling, the crawling sensation of insects moving under the skin, or water trickling down the leg. 

Symptoms are typically worst below the knee, almost always worse at rest, and reliably worse in the evening and at night – which is why the impact on sleep can be so devastating. 

Movement brings temporary relief, but the moment you stop, the sensations return.

The cause is unknown in the majority of cases, though it is thought to involve dopamine signalling in the brain. 

The condition runs in families, suggesting a genetic component. 

It can also be triggered by certain medications – including some antidepressants, antipsychotics, lithium, beta blockers and the anti-sickness drug metoclopramide – as well as by underlying health conditions such as kidney disease, diabetes, Parkinson’s disease and an underactive thyroid. 

RLS affects around one in five women during pregnancy, which is how Molly first encountered the problem.

But there was a clue in Molly’s story that pointed me towards the real culprit. 

She was now in her early forties, and she mentioned, almost in passing, that her periods had changed: heavier than before, lasting a day or so longer, and arriving more frequently – every 24 days instead of her usual 29. 

That shift was significant. Restless legs syndrome can be caused by a deficiency of iron, the crucial nutrient that helps the body transport oxygen. And heavy periods are a known trigger of an iron deficiency.

I ordered a blood test that confirmed Molly’s diagnosis and the cause of her RLS: chronically low iron levels.

The good news is that identifying the cause was the first step to solving the problem.

Molly began a course of oral iron tablets, taken alongside a glass of orange juice – the vitamin C significantly improves iron absorption. She also got a contraceptive hormone coil fitted, which is shown to reduce period bleeding. 

Slowly, as her iron levels recovered, her symptoms began to ease. Eventually, she slept. 

Crucially, it’s not just women with heavy periods who can suffer an iron deficiency. The nutrient is typically found in red meat, certain fish, pulses and leafy green vegetables such as spinach and kale. Anyone who fails to get enough iron can experience RLS.

Moreover, some people appear more sensitive to this deficiency. There are patients whose iron levels need to be maintained well above the minimum threshold on a blood test before restless legs symptoms fully resolve.

But because too much iron can be harmful, this is not something to manage alone – your GP should monitor your levels throughout.

Iron deficiency is one of the most overlooked causes of restless legs syndrome, and it is one of the most treatable. If you have RLS and have never had your iron levels checked, that is the first conversation to have with your doctor.

It is a simple blood test and, if deficiency is the answer, a cheap daily supplement could change your nights entirely.

If iron is not the issue, the next step is to review your medications with your GP – some drugs can provoke or worsen restless legs, though never stop any prescribed medication suddenly without medical advice. 

It is also worth looking at other potential triggers. Caffeine and alcohol are both known to aggravate symptoms and cutting back – or eliminating them temporarily to see what happens – is worth trying. 

Some people find it helpful to keep a food and symptom diary; salty foods, for instance, can make things worse for certain individuals.

Good sleep hygiene matters for everyone, but it is especially important with restless legs. 

That means keeping the bedroom for sleep and sex only, avoiding phones and screens before bed, ensuring the room is dark, cool and quiet, exercising earlier in the day rather than close to bedtime, and keeping consistent sleep and wake times. 

Heat can be particularly helpful for RLS – a warm bath or a heat pad on the legs before bed, combined with stretching or massage, can make a real difference.

When lifestyle changes are not enough, there are medications that can help. Nerve pain tablets pregabalin and gabapentin are both used to treat restless legs, and there are options for pain and sleep too. 

A group of drugs called dopamine agonists – more commonly associated with Parkinson’s disease – used to be the standard first-line treatment, but are now used only occasionally and generally not for the long term. 

They can cause nausea, dizziness and fatigue, and over time they can actually worsen the condition itself. 

Talking therapy can also be valuable – RLS has a real impact on quality of life, and support with the psychological toll of chronic sleep disruption is not something to underestimate.

The outlook with restless legs varies. Roughly a third of people find their symptoms worsen over time, but around a quarter see them improve or even disappear.

Please do not struggle on in silence – see your GP. As Molly discovered, sometimes the answer is simpler than you feared, and a good night’s sleep is closer than it feels.