Comprehensive Effects of Magnesium Supplementation on Cardiometabolic Risk Factors: A Systematic Review and Dose-Response Meta-Analysis

Background: Evidence regarding the impacts of magnesium (Mg) supplementation on cardiometabolic risk factors (CMRFs) remains inconsistent. Objectives: This systematic review and dose-response meta-analysis evaluated effects of Mg supplementation on anthropometric indices, liver and kidney function, lipid and glycemic profiles, blood pressure, and inflammatory biomarkers. Methods: A systematic search of electronic databases up to May 2026 identified 78 eligible randomized controlled trials. Results: Mg supplementation significantly reduced body weight (weighted mean difference [WMD]: -0.70 kg; 95% confidence interval [CI]: -1.30, -0.09), diastolic blood pressure (WMD: -1.58 mmHg; 95% CI: -2.50, -0.65), homeostasis model assessment of insulin resistance (WMD: -0.48; 95% CI: -0.79, -0.18), low-density lipoprotein cholesterol (WMD: -3.21 mg/dL; 95% CI: -5.27, -1.15), fasting blood glucose (WMD: -3.60 mg/dL; 95% CI: -6.13, -1.06), systolic blood pressure (WMD: -2.50 mmHg; 95% CI: -4.08, -0.91), glycated hemoglobin (WMD: -0.15%; 95% CI: -0.26, -0.03), triglycerides (WMD: -9.24 mg/dL; 95% CI: -16.87, -1.61), and interleukin-6 levels (WMD: -1.10 pg/mL; 95% CI: -1.93, -0.27) compared with controls. High-density lipoprotein cholesterol concentrations significantly increased (WMD: 1.45 mg/dL; 95% CI: 0.37, 2.54). No significant effects were identified on hip circumference, alanine aminotransferase, waist circumference, tumor necrosis factor-α, creatinine, C-reactive protein, body mass index, total cholesterol, fasting insulin, body fat percentage, and aspartate aminotransferase. Most RCTs (79.5%) administered Mg doses ≥ 300 mg/day, and 66.7% had intervention durations ≥ 12 weeks; however, evidence from higher-dose (≥500 mg/day) and longer-term (≥25 weeks) interventions remained limited. Conclusions: Mg supplementation was associated with significant improvements in several CMRFs, including body weight, lipid and glycemic profiles, blood pressure, and interleukin-6 levels. However, these effects were generally modest, and their clinical relevance remains uncertain given the variable certainty of evidence across outcomes.