Clinical bottom line
Oral magnesium supplementation is a putative, low-risk intervention for migraine prevention that may modestly reduce attack frequency in some patients, particularly those with magnesium deficiency or migraine with aura. Current evidence suggests a potential benefit, but effect sizes are generally small and heterogeneous across studies. Magnesium supplementation could be considered as an adjunctive preventive option in primary care for patients seeking non-pharmacological approaches or those with contraindications to standard migraine prophylactics. However, definitive recommendations await larger, high-quality randomized controlled trials (RCTs) and clearer dosing guidelines.
What the evidence shows
Magnesium plays a recognized role in migraine pathogenesis, potentially through modulation of neuronal excitability, vascular tone, and neurotransmitter release (Rybicka et al., 2012). Several clinical trials and systematic reviews have explored oral magnesium’s efficacy in migraine prophylaxis, with mixed but generally favorable results.
Teigen Levi et al. (2014) conducted an evidence-based review highlighting that oral magnesium supplementation, particularly magnesium oxide, showed a modest reduction in migraine frequency and intensity in adults. The review noted that magnesium was well tolerated with minimal adverse effects, mainly gastrointestinal symptoms. The authors emphasized that magnesium deficiency is common in migraineurs, which may partly explain the observed benefits.
More recently, Teubert et al. (2025) updated the evidence base, confirming that magnesium supplementation can reduce migraine frequency by approximately 20-30% compared to placebo in some patient populations. Their analysis underscored variability in study designs, magnesium formulations, and dosages, which complicates direct comparisons. They also noted that benefits appeared more pronounced in patients with aura and those with baseline low magnesium levels.
Alghadeer et al. (2016) reviewed different oral magnesium compounds and concluded that magnesium oxide remains the most studied and effective form for migraine prevention, although bioavailability varies among formulations. They also highlighted the need for standardized dosing protocols, with typical daily doses ranging from 300 to 600 mg elemental magnesium.
Cost-effectiveness analyses, such as that by Guerrero-Romero et al. (2022) in related metabolic conditions, suggest that oral magnesium is an inexpensive intervention with a favorable safety profile, supporting its consideration in broader preventive strategies.
Caveats and uncertainty
Despite promising findings, the evidence base for oral magnesium in migraine prevention has limitations. Many RCTs have small sample sizes, heterogeneous patient populations, and variable outcome measures, leading to inconsistent effect estimates. The optimal magnesium formulation, dose, and treatment duration remain unclear.
Adverse effects, while generally mild, primarily involve gastrointestinal discomfort, which may affect adherence. Magnesium supplementation is contraindicated or requires caution in patients with renal impairment or certain cardiac conditions.
Importantly, magnesium deficiency is not universally present in migraine patients, and supplementation may be less effective in those with normal baseline levels. Routine serum magnesium testing is not standardized or widely recommended, complicating patient selection.
Finally, the evidence largely derives from adult populations; data in pediatric or elderly patients are limited. Comparative effectiveness against established pharmacologic prophylactics is also insufficiently studied.
How this may change practice
Primary care clinicians may consider oral magnesium supplementation as a low-risk adjunct or alternative for migraine prevention in selected patients, especially those preferring non-pharmacological options or with contraindications to standard agents. Discussion should include the modest expected benefit, potential gastrointestinal side effects, and the current uncertainty regarding optimal dosing.
Magnesium supplementation could be trialed for 8-12 weeks with monitoring of migraine frequency and tolerability. Clinicians should remain cautious in patients with renal dysfunction and counsel regarding possible interactions with other medications.
Further research is needed before magnesium can be routinely recommended as a first-line preventive therapy. Meanwhile, it may serve as part of a multimodal approach including lifestyle modification and other complementary therapies.