Oral magnesium supplementation reduces ambulatory blood pressure in patients with mild hypertension

Am J Hypertens. 2009 Oct;22(10):1070-5. doi: 10.1038/ajh.2009.126. Epub 2009 Jul 16.


Background: Accumulating evidence implicates a role of Mg(2+) in the pathophysiology of essential hypertension. Previous studies evaluating the antihypertensive efficacy of Mg(2+) supplementation gave contradictory results. This study aimed to investigate the effect of oral Mg(2+) supplementation on 24-h blood pressure (BP) and intracellular ion status in patients with mild hypertension.

Methods: A total of 48 patients with mild uncomplicated hypertension participated in the study. Among them, 24 subjects were assigned to 600 mg of pidolate Mg(2+) daily in addition to lifestyle recommendations for a 12-week period and another 24 age- and sex-matched controls were only given lifestyle recommendations. At baseline and study-end (12 weeks) ambulatory BP monitoring, determination of serum and intracellular ion levels, and 24-h urinary collections for determination of urinary Mg(2+) were performed in all study subjects.

Results: In the Mg(2+) supplementation group, small but significant reductions in mean 24-h systolic and diastolic BP levels were observed, in contrast to control group (-5.6 +/- 2.7 vs. -1.3 +/- 2.4 mm Hg, P < 0.001 and -2.8 +/- 1.8 vs. -1 +/- 1.2 mm Hg, P = 0.002, respectively). These effects of Mg(2+) supplementation were consistent in both daytime and night-time periods. Serum Mg(2+) levels and urinary Mg(2+) excretion were significantly increased in the intervention group. Intracellular Mg(2+) and K(+) levels were also increased, while intracellular Ca(2+) and Na(+) levels were decreased in the intervention group. None of the intracellular ions were significantly changed in the control group.

Conclusion: This study suggests that oral Mg(2+) supplementation is associated with small but consistent ambulatory BP reduction in patients with mild hypertension.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Antihypertensive Agents / therapeutic use*
  • Blood Pressure Monitoring, Ambulatory
  • Dietary Supplements*
  • Humans
  • Hypertension / drug therapy*
  • Hypertension / physiopathology
  • Magnesium / administration & dosage
  • Magnesium / therapeutic use*


  • Antihypertensive Agents
  • Magnesium