What happens to your blood pressure when you take magnesium

Magnesium plays a key role in relaxing blood vessels, which can help lower blood pressure. However, research is mixed on how much magnesium you need to get this effect and how effective the supplements actually are.

Does magnesium lower blood pressure?

Magnesium is thought to help lower blood pressure by keeping blood vessels relaxed. Magnesium also helps keep blood vessels healthy by acting as an antioxidant to counteract damage to blood vessels.

Some studies report that the effect of magnesium on lowering blood pressure is inconclusive or minimal. Others show stronger evidence of a benefit, but results vary depending on the amount of magnesium required to see an effect.

Research findings suggest that magnesium can:

• Lower blood pressure in people deficient in magnesium: An analysis of 34 studies found that taking magnesium significantly reduced blood pressure, but its effectiveness was likely limited to people who were deficient.
• Lower blood pressure in people with untreated hypertension (high blood pressure): Taking 600 milligrams (mg) or more of magnesium daily has helped reduce blood pressure.
• Reducing blood pressure in people with uncontrolled but treated hypertension: Doses of 240 to 607 mg/day helped lower blood pressure in people with uncontrolled but treated high blood pressure.

Magnesium supplementation has also been shown to reduce high blood pressure in people with:

• Diabetes (a condition causing high blood sugar or glucose levels)
• Prediabetes (blood sugar level not high enough to be considered diabetes)
• Insulin resistance (when cells no longer respond well to the hormone insulin and can no longer absorb glucose from the blood, requiring more insulin)
• Heart disease

Magnesium has shown no benefit for people with controlled hypertension or normal blood pressure.

What does magnesium do for the body?

Magnesium is a mineral found in foods, supplements and some medications. It plays an important role in:

• Regulate blood pressure, blood sugar, and muscle and nerve function
• Making proteins, bones and DNA (genetic material)
• Keep bones healthy by increasing body density, thereby reducing the risk of osteoporosis (reduced bone density and mass) and bone fractures

In 2022, the Food and Drug Administration (FDA) approved a qualified health claim allowing foods and supplements containing magnesium to include information on their labels that “a diet containing sufficient magnesium may reduce the risk of high blood pressure”, but the “scientific evidence is inconsistent and inconclusive”.

Magnesium-Rich Foods to Add to Your Diet

It is recommended to obtain magnesium through natural foods rather than supplements or fortified foods (such as breakfast cereals) because natural foods provide additional nutrients, including fiber, with many health benefits.

Foods rich in magnesium include:

• Pumpkin seeds
• Chia Seeds
• Almonds
• Spinach
• Cashew nuts
• Peanuts
• Black beans
• Edamame
• Peanut butter
• Potatoes

The Recommended Dietary Allowance (RDA) for magnesium is 400 mg for men ages 19 to 30 and 420 mg for men ages 31 and older. The RDA for women is 310 mg for ages 19 to 30 and 320 mg for ages 31 and older.

Should I take supplements?

Ideally, you can get the vitamins and minerals your body needs through a nutrient-rich diet. However, dietary supplements may be necessary in some cases if you are unable to achieve the RDA of nutrients through diet alone. Lab tests can determine if you have a magnesium deficiency.

Magnesium deficiency is more likely to occur in people:

• 65 years and over
• With gastrointestinal diseases
• With type 2 diabetes
• With long-term alcohol use disorder

Potential side effects

Magnesium from food is not harmful in any amount and does not need to be limited.

It is recommended that adults consume no more than 350 mg of magnesium per day from dietary supplements or medications. Taking more than the recommended amount may cause:

Magnesium supplements may also interfere with how certain medications work, including:

• Bisphosphonates (used to treat osteoporosis), including Fosamax (alendronate)
• Antibiotics, including tetracyclines such as demeclocycline and Vibramycin (doxycycline), and quinolones such as Cipro (ciprofloxacin) and levofloxacin
• Diuretics (water pills), including Lasix (furosemide), Bumex (bumetanide), Aquazide H (hydrochlorothiazide), Edecrin (ethacrynic acid), Midamor (amiloride), and Aldactone (spironolactone)
• Proton pump inhibitors (PPIs) (medicines used to treat ulcers or acid reflux), including Nexium (esomeprazole magnesium) and Prevacid (lansoprazole)

To avoid potential interactions and side effects, always consult a pharmacist or healthcare professional before starting to take magnesium supplements.