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Magnesium for blood sugar

Goal: What trials of magnesium used in people with diabetes or at high risk of it, and how blood sugar changed.

Each protocol describes what studies used, for one goal or for one group of people. It is not advice for you: talk to a doctor before you start a supplement.

Updated 10 Nov 2026
Dose

300 mg a day as magnesium chloride in people with type 2 diabetes and low blood magnesium. 300 or 600 mg a day as magnesium oxide in a Brazilian trial, where the higher dose improved control.[1]

Form

Magnesium chloride, oxide and aspartate in single trials.[1]

How long

16 weeks with magnesium chloride and 30 days with magnesium oxide.[1] In a 2016 review, fasting glucose improved only in trials of 4 months or longer.[2]

What studies found

A 2021 review of double-blind trials: lower fasting glucose in people with diabetes, and better glucose and insulin sensitivity in people at high risk.[3] A 2026 review of 78 trials: fasting glucose 3.60 mg/dL lower and HbA1c 0.15 percentage points lower, effects its authors called modest.[4]

Ask a doctor first

The American Diabetes Association finds the evidence not enough to recommend magnesium for blood sugar control. In 50 people with type 2 diabetes on insulin, magnesium aspartate had no effect.[1] The US upper limit from supplements is 350 mg a day for adults.[1]

People who take diabetes medicines or have kidney disease should ask a doctor or pharmacist first.[1]

References

  1. Magnesium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  2. A systematic review and meta-analysis of randomized controlled trials on the effects of magnesium supplementation on insulin sensitivity and glucose control. Simental-Mendía LE, Sahebkar A, Rodríguez-Morán M, Guerrero-Romero F Pharmacol Res, 2016. PMID 27329332
  3. Oral Magnesium Supplementation for Treating Glucose Metabolism Parameters in People with or at Risk of Diabetes: A Systematic Review and Meta-Analysis of Double-Blind Randomized Controlled Trials. Veronese N, Dominguez LJ, Pizzol D, Demurtas J, Smith L, Barbagallo M Nutrients, 2021. PMID 34836329
  4. Comprehensive Effects of Magnesium Supplementation on Cardiometabolic Risk Factors: A Systematic Review and Dose-Response Meta-Analysis. Mohammadi S, Palermo A, Ojani P, Alaghemand N, Pirayvatlou PS, Mirkarimi M, et al. Nutrients, 2026. PMID 42588058