Magnesium & Blood Pressure
At Juice Doctor, we love magnesium – not just because the data suggests that many people are deficient, but also because of the long list of potential benefits it offers!
One of those potential benefits, is the role it may play in lowering blood pressure, which has a downstream effect on our organ systems (i.e. brain, heart, kidneys, etc). The numbers in the bracket correspond to the references listed below.
Let’s dive in…
Magnesium supplementation has been shown to produce modest reductions in blood pressure in adults, with the effect size and clinical significance varying by population and baseline magnesium status. Meta-analyses of randomized controlled trials indicate that oral magnesium at doses of approximately 300–400 mg/day for 1–3 months can lower systolic blood pressure (SBP) by about 2–4 mm Hg and diastolic blood pressure (DBP) by 1–3 mm Hg in hypertensive and high-risk populations. The antihypertensive effect is more pronounced in individuals with uncontrolled hypertension or those with comorbidities such as insulin resistance or type 2 diabetes, where reductions in SBP of up to 4–6 mm Hg and DBP of 2–2.5 mm Hg have been observed.[1][2][3][4]
In participants with normal range blood pressure, the effect is smaller but still statistically significant, with reductions in SBP and DBP of approximately 1–3 mm Hg.[5][6] The benefit appears to be dose-dependent, with higher doses (>370–600 mg/day) yielding greater reductions, particularly in untreated hypertensives.[7][3] However, in individuals with well-controlled hypertension or those who are magnesium-replete, supplementation does not consistently lower blood pressure.[7]
Juice Doctor’s Summary of the evidence:
The clinical utility of magnesium as a primary antihypertensive agent remains limited due to the modest effect size. It may be more beneficial in patients who have uncontrolled hypertension, or who are deficient in magnesium to start with. It is less likely to have an effect on those with normal magnesium levels or controlled blood pressure.
We would also argue that reductions in blood pressure by 1-3 or 2-4mmHg, may not be clinically meaningful. What we really care about is if reductions in blood pressure by this amount, lead to improvement in patient outcomes (i.e. decreased risk of stroke, heart attack, kidney failure, etc.). We do not currently have data to say that is the case.
When it comes to blood pressure, it may be reasonable to consider magnesium supplementation as an adjunct in those who have suboptimal magnesium intake or in those with resistant hypertension, mainly because of its favorable safety profile. Stated another way, the data we have at this time suggests that magnesium for blood pressure reduction, is safer than it is effective.
References
1. Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials. Zhang X, Li Y, Del Gobbo LC, et al. Hypertension (Dallas, Tex. : 1979). 2016;68(2):324-33. doi:10.1161/HYPERTENSIONAHA.116.07664.
2. The Effect of Magnesium Supplementation on Blood Pressure in Individuals With Insulin Resistance, Prediabetes, or Noncommunicable Chronic Diseases: A Meta-Analysis of Randomized Controlled Trials. Dibaba DT, Xun P, Song Y, et al. The American Journal of Clinical Nutrition. 2017;106(3):921-929. doi:10.3945/ajcn.117.155291.
3. Effect of Magnesium Supplementation on Blood Pressure: A Meta-Analysis. Kass L, Weekes J, Carpenter L. European Journal of Clinical Nutrition. 2012;66(4):411-8. doi:10.1038/ejcn.2012.4.
4. The Effects of Magnesium Supplementation on Blood Pressure and Obesity Measure Among Type 2 Diabetes Patient: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Asbaghi O, Hosseini R, Boozari B, et al. Biological Trace Element Research. 2021;199(2):413-424. doi:10.1007/s12011-020-02157-0.
5. Magnesium and Potassium Supplementation for Systolic Blood Pressure Reduction in the General Normotensive Population: A Systematic Review and Subgroup Meta-Analysis for Optimal Dosage and Treatment Length. Behers BJ, Behers BM, Stephenson-Moe CA, et al. Nutrients. 2024;16(21):3617. doi:10.3390/nu16213617.
6. Vitamins and Minerals for Blood Pressure Reduction in the General, Normotensive Population: A Systematic Review and Meta-Analysis of Six Supplements. Behers BJ, Melchor J, Behers BM, et al. Nutrients. 2023;15(19):4223. doi:10.3390/nu15194223.
7. Effectively Prescribing Oral Magnesium Therapy for Hypertension: A Categorized Systematic Review of 49 Clinical Trials. Rosanoff A, Costello RB, Johnson GH. Nutrients. 2021;13(1):E195. doi:10.3390/nu13010195.
8. Effects of Magnesium Supplementation in Hypertensive Patients: Assessment by Office, Home, and Ambulatory Blood Pressures. Kawano Y, Matsuoka H, Takishita S, Omae T. Hypertension (Dallas, Tex. : 1979). 1998;32(2):260-5. doi:10.1161/01.hyp.32.2.260.