Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 41000008 · doi:10.1161/HYPERTENSIONAHA.125.25129
What was done
Authors conducted a systematic review, random-effects meta-analysis, and cubic spline dose-response analysis of randomized controlled trials lasting at least 4 weeks to evaluate the effect of magnesium supplementation versus placebo on systolic and diastolic blood pressure. The review included 38 trials with 2,709 participants receiving elemental magnesium doses ranging from 82.3 mg to 637 mg (median 365 mg) for a median duration of 12 weeks.
What was found
Magnesium supplementation reduced systolic blood pressure by -2.81 mm Hg (95% CI, -4.32 to -1.29) and diastolic blood pressure by -2.05 mm Hg (95% CI, -3.23 to -0.88). Subgroup analyses showed greater systolic reductions in hypertensive individuals on blood pressure-lowering medication (-7.68 mm Hg, P < 0.05) and individuals with hypomagnesemia (-5.97 mm Hg, P < 0.05), with corresponding diastolic reductions of -2.96 mm Hg and -4.75 mm Hg (P < 0.05). Changes in normotensive groups did not reach statistical significance. No dose-response relationship was detected (all P >= 0.20).
Why it matters
This meta-analysis demonstrates that magnesium supplementation provides clinically meaningful blood pressure reductions primarily in individuals with preexisting hypertension or baseline hypomagnesemia, rather than in normotensive populations.
Limits
The authors reported high heterogeneity across included studies. The analysis was limited by the lack of an observed dose-response relationship, and the abstract did not report long-term cardiovascular clinical outcomes, adverse event rates, or the specific magnesium formulations used.
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