Magnesium supplements lower blood pressure modestly: meta-analyses put the effect at roughly 3 to 4 mmHg systolic and 2 to 3 diastolic, with bigger drops above 370 mg a day and in people with low baseline intake.
That is a genuine but small effect, worth having as part of a broader plan, not a substitute for medication when pressure is meaningfully high. The food route doubles as good diet advice: leafy greens, nuts, seeds, legumes, and whole grains are magnesium-dense and align with the DASH pattern. If supplementing, studied doses run 300 to 400 mg daily, with citrate or glycinate forms absorbed better than oxide. Know the guardrails: diarrhea is the dose ceiling signal, kidney disease makes magnesium supplementation a doctor-supervised decision, and magnesium binds certain antibiotics and osteoporosis drugs, so separate them by hours. As always, supplements belong on the medication list you show your clinician, especially when you already take blood pressure drugs.
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Common questions
Can magnesium lower blood pressure?
Yes, but modestly, and it is a supplement story, not a replacement for treatment. Meta-analyses of randomized trials, including a 2025 review in the AHA journal Hypertension and an earlier European Journal of Clinical Nutrition analysis, found magnesium supplementation lowers systolic pressure by roughly 3 to 4 mmHg and diastolic by 2 to 3, with larger effects at doses above about 370 mg a day and in people whose intake or levels are low to start. A 3-point drop is real but small: meaningful at the population level, useful as one brick in a lifestyle stack, nowhere near a substitute for medication in stage 2 hypertension. The food-first version is easier and brings the rest of the diet with it: leafy greens, nuts, seeds, beans, and whole grains are magnesium-rich and happen to be DASH-diet staples. If you supplement: typical studied doses are 300 to 400 mg a day, and magnesium citrate or glycinate are absorbed better than oxide. Cautions: the common side effect is loose stools (that is how you know the dose is too high), and people with kidney disease should not take magnesium supplements without medical supervision, because failing kidneys cannot clear the excess. Tell your clinician about any supplement stack; magnesium also interacts with certain antibiotics and bisphosphonates by blocking their absorption.