Which magnesium is best for migraines? Magnesium supplementation has emerged as a potential preventive approach for individuals experiencing recurrent migraines, with several formulations available in the UK. Research suggests that magnesium deficiency may contribute to migraine pathophysiology, and supplementation can help regulate neurological function and vascular tone. Whilst not a first-line treatment under NICE guidelines, magnesium represents a reasonable option for patients seeking non-pharmaceutical approaches or those unable to tolerate conventional preventive medications. This article examines the different types of magnesium supplements, their effectiveness in migraine prevention, recommended dosages, and important safety considerations to help you make an informed decision.

How Magnesium Helps Prevent Migraines

Magnesium plays a crucial role in neurological function and vascular regulation, both of which are implicated in migraine pathophysiology. Research suggests that individuals who experience migraines may have lower magnesium levels compared to those without the condition, though the exact relationship remains an area of ongoing investigation.

The mineral contributes to migraine prevention through several proposed mechanisms. Magnesium acts as a natural calcium channel blocker, helping to regulate neurotransmitter release and prevent the excessive neuronal excitation associated with migraine attacks. It influences the release of calcitonin gene-related peptide (CGRP) and other neuropeptides involved in pain transmission. Additionally, magnesium helps maintain normal vascular tone and may prevent the cortical spreading depression—a wave of electrical activity across the brain—that is thought to trigger migraine aura.

Clinical evidence supporting magnesium supplementation for migraine prevention has been examined in multiple studies. A systematic review published in the Cochrane Database found that magnesium supplementation may reduce migraine frequency in some individuals, though the quality of evidence is generally low to moderate. The European Academy of Neurology (EAN) and the American Academy of Neurology have both acknowledged magnesium as a potentially effective preventive treatment, particularly for individuals with documented magnesium deficiency.

Whilst magnesium supplementation is not a first-line treatment according to NICE guidelines (CG150), it represents a reasonable option for patients seeking non-pharmaceutical approaches or those who cannot tolerate conventional preventive medications. It's important to note that magnesium products for migraine are generally classified as food supplements rather than licensed medicines in the UK. The response to magnesium varies considerably between individuals, and benefits typically emerge after several weeks of consistent supplementation rather than providing immediate relief during acute attacks.

Types of Magnesium Supplements Available in the UK

The UK market offers numerous magnesium formulations, each with distinct characteristics affecting absorption, tolerability, and suitability for migraine prevention. Understanding these differences helps patients and healthcare professionals make informed choices.

Magnesium oxide is one of the most commonly available and economical forms. It contains a high percentage of elemental magnesium by weight (approximately 60%), but has relatively poor bioavailability—meaning the body absorbs only a small proportion of the magnesium content. This form is more likely to cause gastrointestinal side effects, particularly loose stools, due to the unabsorbed magnesium remaining in the digestive tract.

Magnesium citrate combines magnesium with citric acid, creating a compound with generally better absorption than oxide forms. It is well-tolerated by most individuals and represents a good balance between bioavailability and cost. The citrate form also has mild laxative properties, which may be beneficial for individuals experiencing constipation but problematic for those with sensitive digestive systems.

Magnesium glycinate (or bisglycinate) binds magnesium to the amino acid glycine, which may improve absorption and reduce gastrointestinal disturbance compared to some other forms. This chelated form is often recommended for individuals requiring higher doses or those with sensitive stomachs, though direct comparative evidence in migraine studies is limited.

Other formulations available include magnesium malate (combined with malic acid) and magnesium taurate (bound to the amino acid taurine). Magnesium threonate is sometimes marketed for neurological conditions, though evidence for its effectiveness specifically in migraine prevention is very limited. Topical magnesium preparations, such as oils and bath salts containing magnesium chloride, are also marketed, but there is insufficient clinical evidence to support their use in migraine prevention compared to oral supplementation.

When selecting a magnesium supplement, it's important to check labels for the elemental magnesium content and to choose reputable UK-registered products from reliable manufacturers.

Which Magnesium Is Best for Migraines

When selecting magnesium specifically for migraine prevention, several factors warrant consideration, including bioavailability, tolerability, evidence base, and individual patient circumstances.

Magnesium citrate and magnesium oxide have been most commonly studied in migraine prevention trials. Magnesium citrate generally offers better absorption compared to magnesium oxide and may be better tolerated by many individuals. It is widely available in the UK, reasonably priced, and suitable for most people seeking magnesium supplementation for migraines.

Magnesium glycinate may be an alternative option, particularly for patients who experience gastrointestinal side effects with other forms. Its chelated structure may help reduce digestive upset, making it potentially suitable for long-term supplementation. However, it's important to note that direct comparative evidence for superior efficacy specifically in migraine prevention is limited.

Magnesium oxide, despite having lower bioavailability, has been used in several migraine clinical trials. Achieving therapeutic magnesium levels may require higher doses, which often cause diarrhoea and abdominal discomfort. However, it remains a cost-effective option and may be suitable for individuals who tolerate it well.

For patients seeking alternatives, magnesium malate combines reasonable bioavailability with potential energy-supporting properties through its malic acid component. However, specific evidence for its effectiveness in migraine prevention is limited compared to citrate and oxide forms.

Ultimately, the most appropriate magnesium supplement depends on individual tolerance, budget, and response. Many healthcare professionals recommend starting with magnesium citrate due to its favourable balance of absorption, tolerability, and cost. If gastrointestinal side effects occur, switching to glycinate or reducing the dose whilst gradually increasing may improve tolerance. Patients should maintain consistent supplementation for at least 8–12 weeks before evaluating effectiveness, as benefits accumulate over time.

Recommended Dosage and How to Take Magnesium for Migraines

Clinical studies investigating magnesium for migraine prevention have employed various dosing regimens, with most evidence supporting daily doses between 400–600 mg of elemental magnesium. It is essential to distinguish between the total weight of the magnesium compound and the elemental magnesium content, as supplement labels may list either figure.

For migraine prevention, a typical starting dose is 400 mg of elemental magnesium daily, which can be taken as a single dose or divided into two doses (morning and evening). The NHS advises that the safe upper limit for magnesium supplementation is 400 mg daily for adults. Higher doses up to 600 mg daily (as used in some clinical trials) should only be considered under the supervision of a GP or pharmacist. When calculating dosage, patients must check product labels for the elemental magnesium content, as this varies considerably between products and formulations.

Timing and administration considerations can influence both effectiveness and tolerability:

• Taking magnesium with food generally reduces gastrointestinal side effects and may help with consistency of use

• Dividing the daily dose (e.g., 200 mg twice daily) may enhance tolerance compared to a single large dose

• Evening administration may be preferable for some individuals, as magnesium can have mild relaxing properties

• Maintaining consistent timing helps establish routine and may optimise steady-state magnesium levels

Patients should begin with lower doses and gradually increase over 1–2 weeks to minimise digestive upset. If diarrhoea occurs, reducing the dose temporarily and then increasing more slowly often resolves the issue. Switching to a different form may also help with tolerability.

Magnesium supplementation for migraine prevention requires patience, as benefits typically emerge after 8–12 weeks of consistent use. Patients should maintain a headache diary to track migraine frequency, severity, and duration, enabling objective assessment of treatment response. It is worth noting that magnesium works as a preventive measure rather than an acute treatment, so it will not provide immediate relief during a migraine attack.

Potential Side Effects and Safety Considerations

Magnesium supplementation is generally well-tolerated when used appropriately, though certain side effects and safety considerations warrant attention, particularly for individuals with specific health conditions or those taking concurrent medications.

Common side effects are predominantly gastrointestinal and dose-dependent:

• Diarrhoea and loose stools represent the most frequent adverse effect, particularly with magnesium oxide and higher doses of citrate forms

• Abdominal cramping and bloating may occur, especially when initiating supplementation

• Nausea, though less common, can affect some individuals

• These effects typically resolve with dose reduction, slower titration, or switching to more bioavailable forms

Serious adverse effects are rare in individuals with normal kidney function, as the kidneys efficiently excrete excess magnesium. However, hypermagnesaemia (elevated blood magnesium levels) can occur in certain circumstances and may cause muscle weakness, hypotension, cardiac arrhythmias, and in severe cases, respiratory depression. This risk is substantially elevated in individuals with chronic kidney disease (CKD), who should avoid magnesium supplementation unless specifically advised and monitored by their nephrologist or GP.

Drug interactions require consideration:

• Magnesium can reduce absorption of certain antibiotics (tetracyclines, quinolones) and bisphosphonates—these medications should be taken at least 2–4 hours apart from magnesium supplements (check specific product information)

• Magnesium may reduce absorption of levothyroxine and iron supplements; separate by at least 2 hours

• Concurrent use with diuretics may affect magnesium levels (some diuretics increase magnesium loss, whilst potassium-sparing diuretics may increase retention)

• Long-term use of proton pump inhibitors (PPIs) can cause low magnesium levels; if you're taking a PPI and develop symptoms like muscle cramps, consider discussing magnesium testing with your GP

Pregnant and breastfeeding women should consult their GP, midwife or pharmacist before starting magnesium supplementation, though magnesium is generally considered safe during pregnancy when used at recommended doses.

If you experience any suspected side effects from magnesium supplements, report them through the MHRA Yellow Card scheme, which helps monitor the safety of supplements and medicines.

When to Seek Medical Advice About Migraines

Whilst magnesium supplementation represents a reasonable self-management approach for some migraine sufferers, certain circumstances necessitate professional medical evaluation to exclude serious underlying conditions and ensure appropriate treatment.

Patients should consult their GP before starting magnesium supplementation if they:

• Have chronic kidney disease or significantly impaired renal function

• Take regular medications, particularly those mentioned in the interactions section

• Are pregnant, planning pregnancy, or breastfeeding

• Have a history of cardiac arrhythmias or heart block

• Experience frequent migraines (more than 4 days per month) that significantly impact quality of life

Urgent medical attention is required for headaches with the following characteristics, which may indicate serious pathology rather than typical migraine:

• Sudden onset of severe headache reaching maximum intensity within seconds to minutes ("thunderclap headache") – call 999 or go to A&E immediately, as this may indicate subarachnoid haemorrhage

• Headache accompanied by fever, neck stiffness, confusion, or altered consciousness, suggesting possible meningitis or encephalitis – seek emergency care

• New headache in individuals over 50 years, particularly with scalp tenderness or jaw claudication, raising concern for giant cell arteritis

• Headache following head trauma

• Progressive worsening of headache pattern or new neurological symptoms (weakness, visual loss, speech difficulties)

• Headache triggered by exertion, coughing, or sexual activity

If you're unsure whether your symptoms require urgent attention, contact NHS 111 for advice.

NICE guidelines (CG150) recommend that patients experiencing frequent migraines should be offered a formal diagnosis and discussion of preventive treatment options. According to the British Association for the Study of Headache (BASH), preventive treatment should be considered when migraines significantly impact quality of life despite acute treatment. If magnesium supplementation has been tried for 3 months without benefit, or if migraines significantly impair daily functioning despite supplementation, patients should return to their GP to discuss alternative preventive medications such as propranolol, topiramate, or amitriptyline.

Patients should also seek medical review if they experience new or concerning symptoms whilst taking magnesium supplements, particularly signs of hypermagnesaemia such as muscle weakness, irregular heartbeat, or breathing difficulties. Maintaining open communication with healthcare professionals ensures safe, effective migraine management tailored to individual needs and circumstances.

Frequently Asked Questions