Magnesium nudges nearly every heart-risk number, but only slightly

Magnesium is involved in blood pressure regulation, glucose handling and lipid metabolism, and supplements are cheap, widely available and widely taken. Yet trial evidence on whether supplementation actually improves cardiometabolic risk factors has been inconsistent, with individual studies pointing in different directions. This review set out to settle the picture across the full spread of outcomes, from body measurements and liver and kidney function to cholesterol, blood glucose, blood pressure and inflammatory markers, and to examine whether dose and duration change the answer.

The authors systematically searched electronic databases up to May 2026 and identified 78 eligible randomised controlled trials of magnesium supplementation. Results were pooled as weighted mean differences against control groups across anthropometric, metabolic, blood pressure and inflammatory outcomes, with dose-response analysis on top. Most trials (79.5%) used doses of at least 300 mg per day, and 66.7% ran for 12 weeks or longer, though evidence at 500 mg per day or more and beyond 25 weeks was limited.

Magnesium significantly lowered systolic blood pressure by 2.50 mmHg and diastolic by 1.58 mmHg, fasting glucose by 3.60 mg/dL, glycated haemoglobin by 0.15%, LDL cholesterol by 3.21 mg/dL and triglycerides by 9.24 mg/dL, while HDL cholesterol rose by 1.45 mg/dL. Body weight fell by 0.70 kg, insulin resistance scores improved, and the inflammatory marker interleukin-6 dropped. Plenty did not move: waist and hip circumference, body mass index, body fat percentage, total cholesterol, fasting insulin, liver enzymes, creatinine, C-reactive protein and tumour necrosis factor alpha all showed no significant change.

This is one of the broadest syntheses of magnesium trials to date, and it largely confirms the direction of earlier, smaller reviews: consistent but modest benefits across blood pressure, glucose and lipids. The authors are candid that the effects are generally small and that their clinical relevance is uncertain, with the certainty of evidence varying across outcomes. Whether higher doses or longer courses achieve more remains an open question, because trials at 500 mg per day or above and past 25 weeks are scarce.

The takeaway is calibration rather than hype: magnesium supplementation shifted a long list of cardiometabolic numbers in the right direction, but each shift was small, on the order of a couple of points of blood pressure or a few mg/dL of cholesterol or glucose. That pattern is a reason to view magnesium as a possible minor helper for metabolic health, not a substitute for the interventions that move these markers substantially. Anyone weighing it up should note the uncertainty the reviewers themselves flag.