Restless legs syndrome (RLS) affects approximately 5–10% of UK adults, causing uncomfortable sensations and an irresistible urge to move the legs, particularly at night. Whilst magnesium for restless legs is sometimes suggested as a natural remedy, the evidence supporting its use remains limited. Magnesium plays a role in nerve and muscle function, leading to the hypothesis that supplementation might help, but current NICE guidance does not recommend it as a proven treatment. This article examines the available evidence, practical considerations, and safety aspects of using magnesium for RLS, alongside established treatment approaches.

What Is Restless Legs Syndrome and How Does Magnesium Help?

Restless legs syndrome (RLS), also known as Willis-Ekbom disease, is a neurological disorder characterised by an overwhelming urge to move the legs, typically accompanied by uncomfortable sensations. These symptoms usually worsen during periods of rest or inactivity, particularly in the evening and at night, often disrupting sleep and significantly affecting quality of life. The sensations are commonly described as crawling, tingling, burning, or aching deep within the legs, and are temporarily relieved by movement.

The exact cause of RLS remains incompletely understood, though it is believed to involve dysfunction in the brain's dopaminergic pathways and iron metabolism. Primary RLS appears to have a genetic component, whilst secondary RLS may be associated with iron deficiency, pregnancy, chronic kidney disease, or certain medications. The condition affects approximately 5–10% of adults, with women being affected more frequently than men.

Diagnostic criteria for RLS include: an urge to move the legs usually accompanied by uncomfortable sensations; symptoms that begin or worsen during periods of rest; symptoms that are partially or totally relieved by movement; and symptoms that are worse in the evening or night. It's important to distinguish RLS from other conditions such as leg cramps, peripheral neuropathy, or medication-induced akathisia.

Magnesium's potential role in managing RLS is theoretical and not firmly established. As an essential mineral, magnesium is involved in neuromuscular function and nerve transmission. It plays a role in muscle relaxation and nerve function, which has led to the hypothesis that it might help with RLS symptoms. Some researchers have proposed that magnesium deficiency could contribute to the nervous system symptoms observed in RLS, but this remains speculative.

Whilst magnesium supplementation might theoretically help reduce abnormal nerve sensations and muscle tension, it is important to note that there is no scientific consensus establishing magnesium deficiency as a primary cause of RLS, nor strong evidence supporting its use as a primary treatment.

Evidence for Magnesium in Treating Restless Legs

The scientific evidence supporting magnesium supplementation for restless legs syndrome remains limited and somewhat inconsistent. Whilst some small studies have suggested potential benefits, the overall body of research does not yet provide robust support for magnesium as a treatment for RLS.

A frequently cited study published in 2012 examined magnesium supplementation in patients with insomnia, some of whom also experienced RLS symptoms. This small trial suggested that magnesium might improve sleep quality and reduce leg discomfort in certain individuals. However, the study had methodological limitations, including a small sample size and lack of specific focus on RLS as a primary outcome. Other preliminary research has explored the relationship between serum magnesium levels and RLS severity, with mixed results—some studies finding lower magnesium levels in RLS patients, whilst others have found no significant correlation.

Current clinical guidelines from NICE (National Institute for Health and Care Excellence) do not include magnesium supplementation as a recommended treatment for RLS. The NICE Clinical Knowledge Summary (CKS) on restless legs syndrome focuses primarily on lifestyle modifications, iron supplementation when deficiency is confirmed (particularly when serum ferritin is below 75 µg/L), and pharmacological treatments for moderate to severe cases. First-line pharmacological options typically include dopamine agonists (such as ropinirole or pramipexole) or alpha-2-delta ligands (such as pregabalin or gabapentin). The European Academy of Neurology guidelines similarly do not list magnesium as an evidence-based intervention.

Pregnancy-related RLS represents a specific context where magnesium has been studied, as both conditions commonly co-occur during the second and third trimesters. Some observational evidence suggests magnesium supplementation might provide modest benefit in this population, though well-designed randomised controlled trials are lacking. In pregnant women with RLS, checking iron status is particularly important, as iron supplementation is the primary approach when deficiency is identified.

Overall, whilst magnesium supplementation is generally safe and may help some individuals—particularly those with documented deficiency—there is insufficient high-quality evidence to recommend it as a proven treatment for RLS. Patients with significant symptoms should discuss evidence-based treatments with their GP.

How to Use Magnesium for Restless Legs Syndrome

If you are considering trying magnesium for restless legs syndrome, it is advisable to consult your GP or healthcare provider first, particularly if you have existing medical conditions or take regular medications. Your doctor can assess whether magnesium supplementation is appropriate for you and can check for underlying causes of RLS, such as iron deficiency (particularly if serum ferritin is below 75 µg/L), medication side effects, or other conditions that may require different management approaches.

There is no established evidence-based guidance on the timing of supplementation specifically for RLS. Since symptoms typically worsen in the evening and at night, some people find it helpful to take magnesium supplements in the evening, but this is based on individual preference rather than clinical evidence. Finding what works best for you may require some trial and error.

Magnesium can be obtained through dietary sources as well as supplements. Foods rich in magnesium include green leafy vegetables (spinach, kale), nuts and seeds (almonds, pumpkin seeds), whole grains, legumes, dark chocolate, and fish. The UK Reference Nutrient Intake (RNI) for magnesium is 300 mg daily for men and 270 mg daily for women. Increasing dietary magnesium intake is generally the safest first approach and carries minimal risk of adverse effects.

For those considering topical magnesium products, such as magnesium oil or Epsom salt (magnesium sulfate) baths, it's important to note that evidence for significant transdermal absorption is limited. Some individuals report subjective benefit, but this may be due to the relaxing effects of warm baths rather than magnesium absorption. If you choose to try Epsom salt baths, follow product instructions rather than using specific quantities.

Lifestyle measures that may help manage RLS include maintaining good sleep hygiene, moderate regular exercise (though avoiding intense exercise close to bedtime), and reducing caffeine and alcohol consumption, particularly in the evening. These approaches are recommended by NICE alongside appropriate medical treatment.

It is important to maintain realistic expectations. If magnesium is going to help your symptoms, you might notice improvement within several weeks, though this varies considerably between individuals. If you experience no benefit after 4–6 weeks of consistent use, or if your symptoms worsen, you should return to your GP for further assessment and discussion of evidence-based treatments.

Magnesium Dosage and Forms for Restless Legs

Magnesium supplements are available in numerous forms, which differ in their absorption rates, bioavailability, and potential side effects. The most commonly available forms in the UK include:

• Magnesium citrate – generally well absorbed; may have a mild laxative effect

• Magnesium glycinate – typically well absorbed and often causes less digestive upset

• Magnesium oxide – less well absorbed but commonly found in multivitamins; more likely to cause loose stools

• Magnesium malate – generally well tolerated

• Magnesium chloride – available in both oral and topical preparations

The absorption and tolerability of different magnesium forms vary between individuals. If one form causes digestive discomfort, trying another form may be helpful.

Dosage recommendations for magnesium supplementation in RLS have not been established through clinical trials. Typical supplemental doses range from 200–400 mg of elemental magnesium daily. It is crucial to check the label for elemental magnesium content, as different magnesium compounds contain varying amounts—for example, magnesium citrate products typically contain only a fraction of elemental magnesium by weight.

The UK Expert Group on Vitamins and Minerals has established a guidance level of 400 mg daily for supplemental magnesium (not including dietary sources) for adults. Exceeding this amount increases the risk of adverse effects, particularly diarrhoea. It is generally advisable to start with a lower dose (100–200 mg) and gradually increase if needed and tolerated. Using the lowest effective dose is recommended.

Special considerations apply to certain populations. Individuals with chronic kidney disease should not take magnesium supplements without medical supervision, as impaired renal function can lead to dangerous magnesium accumulation. Those taking certain medications, including some antibiotics, bisphosphonates, and diuretics, should discuss potential interactions with their pharmacist or GP. Pregnant or breastfeeding women should seek medical advice before starting supplementation, although magnesium is generally considered safe during pregnancy when used appropriately.

If you're unsure about which magnesium product to choose or how to interpret the elemental magnesium content, consult a pharmacist for guidance.

Side Effects and Safety Considerations

Magnesium supplementation is generally well tolerated when used at recommended doses, but side effects can occur, particularly with higher doses or certain formulations. The most common adverse effect is gastrointestinal disturbance, including loose stools, diarrhoea, nausea, and abdominal cramping. These effects are dose-dependent and more likely with poorly absorbed forms such as magnesium oxide. If digestive symptoms occur, reducing the dose or switching to a different form may help.

Serious side effects are rare in individuals with normal kidney function but can occur with excessive intake. Magnesium toxicity (hypermagnesaemia) may cause muscle weakness, low blood pressure, irregular heartbeat, confusion, and in severe cases, cardiac arrest or respiratory depression. This is extremely uncommon from oral supplementation alone but is a significant risk in people with impaired renal function. Symptoms requiring immediate medical attention include severe muscle weakness, difficulty breathing, or marked changes in heart rhythm.

Drug interactions should be carefully considered. Magnesium can reduce the absorption of certain medications:

• Levothyroxine – separate by at least 4 hours

• Tetracycline and quinolone antibiotics – separate by 2-4 hours (check specific product advice)

• Bisphosphonates (used for osteoporosis) – separate by at least 2 hours

• Gabapentin – separate from magnesium/aluminium-containing antacids by at least 2 hours

Magnesium may also enhance the effects of muscle relaxants and blood pressure medications. Additionally, long-term use of proton pump inhibitors (PPIs) can cause hypomagnesaemia in some people, which may warrant monitoring if you develop symptoms.

When to seek medical advice: Contact your GP if you experience persistent or severe side effects, if your RLS symptoms significantly worsen, or if you develop new symptoms. Urgent medical attention is needed for symptoms such as unilateral leg swelling or redness (possible deep vein thrombosis), acute neurological symptoms, or chest pain/shortness of breath.

It is also important to seek medical review if restless legs symptoms are severely affecting your sleep or daily functioning, as prescription medications with stronger evidence bases may be appropriate. Additionally, if you have not had recent blood tests, your doctor may wish to check your iron studies (serum ferritin) and renal function, as iron deficiency is a treatable cause of RLS, and kidney function affects magnesium handling.

If you experience side effects that you suspect may be related to magnesium supplements, you can report them through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk). Never exceed recommended doses without medical supervision.

Frequently Asked Questions