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Magnesium for blood pressure

Goal: What trials of magnesium supplements used in adults, and how much blood pressure fell.

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

82 to 637 mg of magnesium a day, median 365 mg, in a 2025 review of 38 trials.[1] Higher doses did not give larger drops.[1]

How long

At least 4 weeks, median 12 weeks.[1] In a 2016 review, 1 month, or 300 mg a day, was enough to raise blood magnesium and lower blood pressure.[2]

What studies found

38 trials with 2,709 people: systolic pressure 2.81 mmHg and diastolic 2.05 mmHg lower than with placebo. In people with high blood pressure on medicines, 7.68 and 2.96 mmHg. In people with low blood magnesium, 5.97 and 4.75 mmHg. Not significant in people with normal blood pressure.[1] A 2006 Cochrane review of 12 smaller trials judged the evidence weak and probably due to bias.[3]

Ask a doctor first

The US upper limit for magnesium from supplements is 350 mg a day for adults, and the EU limit is 250 mg.[4][5] People with kidney disease have a higher risk of magnesium toxicity, and diuretics change the body's magnesium level.[4]

People who have high blood pressure or take a medicine every day should ask a doctor or pharmacist first.[4]

References

  1. Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Argeros Z, Xu X, Bhandari B, Harris K, Touyz RM, Schutte AE Hypertension, 2025. PMID 41000008
  2. Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials. Zhang X, Li Y, Del Gobbo LC, Rosanoff A, Wang J, Zhang W, et al. Hypertension, 2016. PMID 27402922
  3. Magnesium supplementation for the management of essential hypertension in adults. Dickinson HO, Nicolson DJ, Campbell F, Cook JV, Beyer FR, Ford GA, et al. Cochrane Database Syst Rev, 2006. PMID 16856052
  4. Magnesium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  5. Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF) and the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). European Food Safety Authority (EFSA), 2025. www.efsa.europa.eu