Effectively Prescribing Oral Magnesium Therapy for Hypertension: A Categorized Systematic Review of 49 Clinical Trials

Nutrients. 2021 Jan 10;13(1):195. doi: 10.3390/nu13010195.


Trials and meta-analyses of oral magnesium for hypertension show promising but conflicting results. An inclusive collection of 49 oral magnesium for blood pressure (BP) trials were categorized into four groups: (1) Untreated Hypertensives; (2) Uncontrolled Hypertensives; (3) Controlled Hypertensives; (4) Normotensive subjects. Each group was tabulated by ascending magnesium dose. Studies reporting statistically significant (p < 0.05) decreases in both systolic BP (SBP) and diastolic BP (DBP) from both baseline and placebo (if reported) were labeled "Decrease"; all others were deemed "No Change." Results: Studies of Untreated Hypertensives (20 studies) showed BP "Decrease" only when Mg dose was >600 mg/day; <50% of the studies at 120-486 mg Mg/day showed SBP or DBP decreases but not both while others at this Mg dosage showed no change in either BP measure. In contrast, all magnesium doses (240-607 mg/day) showed "Decrease" in 10 studies on Uncontrolled Hypertensives. Controlled Hypertensives, Normotensives and "magnesium-replete" studies showed "No Change" even at high magnesium doses (>600 mg/day). Where magnesium did not lower BP, other cardiovascular risk factors showed improvement. Conclusion: Controlled Hypertensives and Normotensives do not show a BP-lowering effect with oral Mg therapy, but oral magnesium (≥240 mg/day) safely lowers BP in Uncontrolled Hypertensive patients taking antihypertensive medications, while >600 mg/day magnesium is required to safely lower BP in Untreated Hypertensives; <600 mg/day for non-medicated hypertensives may not lower both SBP and DBP but may safely achieve other risk factor improvements without antihypertensive medication side effects.

Keywords: anti-hypertensive medications; blood pressure; hypertension; magnesium; oral magnesium therapy.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Administration, Oral
  • Antihypertensive Agents / administration & dosage*
  • Antihypertensive Agents / therapeutic use*
  • Blood Pressure / drug effects
  • Cardiovascular Diseases
  • Clinical Trials as Topic
  • Databases, Factual
  • Humans
  • Hypertension / drug therapy*
  • Magnesium / administration & dosage*
  • Magnesium / therapeutic use*
  • Risk Factors


  • Antihypertensive Agents
  • Magnesium