Magnesium is a mineral vital for the proper functioning of your body.

Your body can’t make it, so you need to obtain it from your diet.

To get enough of this essential nutrient, it’s recommended that men and women get 400–420 mg and 320–360 mg per day, respectively and depending on age (1).

You can achieve this by eating magnesium-rich foods or by taking supplements.

This article looks at the benefits, side effects, and recommended dosages of magnesium supplements.

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Magnesium is the fourth most abundant mineral in your body, and your body can’t work properly without it (2).

The nutrient is essential for hundreds of metabolic processes and many other important bodily functions — from producing energy to building important proteins like your DNA (3).

Dietary sources of magnesium include legumes, nuts, seeds, and green leafy vegetables. Smaller amounts are found in meat and fish.

However, despite its importance, studies show that almost 50% of people in Western countries in Europe and the United States don’t get enough of this essential mineral (2, 4).

Moreover, low levels of magnesium are linked to a number of health conditions, such as type 2 diabetes, heart disease, and Alzheimer's (2).

Summary Magnesium is a mineral that your body needs to function properly. Many people are deficient in this essential nutrient, which is found in foods like nuts, leafy greens, legumes, and seeds.

Getting enough magnesium is important for keeping your body functioning optimally.

Though it’s possible to get adequate amounts of this mineral from your diet, taking a supplement may be helpful if you struggle to meet your needs through food or if you’re deficient.

Taking a magnesium supplement and correcting a deficiency has been linked to health benefits. These include a lower risk of conditions like heart disease and improved blood pressure, mood, and blood sugar control.

Can Reduce Blood Pressure

Taking magnesium supplements may help reduce blood pressure levels (5).

Studies show that people with high blood pressure may experience improvements when supplementing with this mineral (6, 7).

In fact, one review of 22 studies found that supplementing with an average of 410 mg of magnesium daily was associated with a 3–4 mm Hg drop in systolic blood pressure (the top number) and a 2–3 mm Hg drop in diastolic blood pressure (the bottom number) (8).

Similarly, a recent review of 34 studies concluded that taking around 350 mg per day of magnesium for an average of 3 months significantly reduced systolic blood pressure by 2.00 mm Hg and diastolic blood pressure by 1.78 mm Hg (9).

May Improve Mood

Some studies link low levels of magnesium with depression, which has led researchers to wonder whether supplementing with this mineral could help treat this condition (10).

One 12-week randomized controlled trial in older adults with type 2 diabetes, magnesium deficiency, and depression found that 450 mg of magnesium daily was as effective as a 50 mg dose of the antidepressant Imipramine at improving depressive symptoms (11).

Another 6-week study in 126 people with mild or moderate depression observed that those who took 248 mg per day of the mineral, alongside their normal treatment, reported a significant improvement in depression scores (12).

However, these studies were not blinded, meaning that the participants knew that they received the mineral, which could skew the results.

Ultimately, larger and longer studies in this area are needed.

May Benefit Blood Sugar Control

Magnesium plays a crucial role in insulin and glucose metabolism. Many people with type 2 diabetes — a condition impacting blood sugar control — are deficient in this nutrient (2).

In part, this is because high blood sugar or insulin levels can increase how much of this nutrient you lose through your urine (13).

It’s been suggested that taking magnesium supplements may improve insulin resistance, a metabolic problem in which your cells don’t respond to insulin.

Insulin is an important hormone that helps regulate your blood sugar levels. Thus, improving insulin resistance can promote better blood sugar control — especially in people with diabetes.

In a 3-month study, people with type 2 diabetes who took 300 mg per day of magnesium experienced significant reductions in fasting and post-meal blood sugar levels compared to the placebo group (14).

Additionally, a review found that taking magnesium supplements for more than four months had a beneficial effect on insulin sensitivity and blood sugar control (15).

Though more research is needed, magnesium supplements seem to be effective at helping control blood sugar in people with type 2 diabetes (13).

May Reduce Heart Disease Risk

Low levels of magnesium have been linked to an increased risk of heart disease (16, 17).

This may be because low levels of this mineral negatively affect risk factors for heart disease like blood sugar control and blood pressure (17).

A recent review of 28 studies concluded that magnesium supplements positively affected some heart disease risk factors in people with type 2 diabetes by lowering blood pressure, cholesterol levels, and fasting blood sugar (18).

This means that taking magnesium supplements may help reduce heart disease risk factors, especially in people who are deficient (19).

While these results are promising, more studies in this area are needed.

May Improve Migraine

Low levels of magnesium have been linked to migraine, a condition characterized by intense, recurring headaches (20).

One 12-week study found that people with migraine who took a daily supplement containing 600 mg of magnesium experienced 42% fewer migraine attacks, and the attacks were less intense (21).

Another review of 5 studies showed that treating migraine with 600 mg of magnesium — a high-level dose — was safe and effective (22).

Still, more studies are needed before firm dosage recommendations can be made for treating migraine.

Summary Magnesium supplements may improve a number of health markers, such as blood pressure and blood sugar control. It may also reduce your risk of health conditions such as heart disease, migraine, and depression.

Though magnesium supplements are generally considered safe, you should check with your healthcare provider before taking them — especially if you have a medical condition.

The mineral supplement may be unsafe for people who take certain diuretics, heart medications, or antibiotics (1).

Most people who take magnesium supplements don’t experience side effects, but it can cause gut related issues, such as diarrhea, nausea, and vomiting — especially in large doses (20).

It’s important to note that people with kidney issues are at a higher risk of experiencing adverse effects related to these supplements (23).

Additionally, evidence to suggest that magnesium supplements benefit people who are not deficient is insufficient.

Summary Magnesium supplements are generally considered safe. However, you should speak to your healthcare provider before taking these supplements if you have a health condition or are taking any medications.

A diet high in magnesium includes healthy whole foods like whole grains, nuts, seeds, and legumes.

Though it’s possible to get the daily recommended amount of the mineral — 400–420 mg for men and 320–360 mg for women — through diet alone, most modern diets are low in magnesium-rich foods.

If you can’t get enough magnesium through your diet and if it’s safe for you to do so, you may want to take a supplement.

How Much Should You Take?

Recommended doses of magnesium supplements are 200–400 mg per day, depending on the brand.

This means that a supplement can provide you with 100% or more of the reference daily intake (RDI).

The Food and Nutrition Board of the Institute of Medicine in the United States has set an upper tolerable limit of 350 mg per day for supplemental magnesium — below which you are unlikely to experience any digestive side effects (1, 23).

If you’re deficient, you may need a higher dose, but you should check with your healthcare provider before taking large doses of magnesium that exceed the RDI.

Which Type Should You Choose?

Magnesium supplements come in a variety of forms, some of which your body can absorb better than others.

Types of this mineral that are better absorbed include (23, 24):

  • Magnesium citrate
  • Magnesium lactate
  • Magnesium aspartate
  • Magnesium chloride
  • Magnesium malate
  • Magnesium taurate

However, other factors — such as your genes and whether you have a deficiency — may also influence absorption (20).

Additionally, while many studies show that certain types of magnesium supplements are more absorbable than others, some studies find no difference between the various formulations (25).

When shopping for a magnesium supplement, choose brands with a U.S. Pharmacopeia (USP) mark, which indicates that the supplement has been tested for potency and contaminants.

Summary The tolerable upper limit for supplemental magnesium is 350 mg per day. Your body may absorb some forms of magnesium better than others.

The mineral magnesium is essential for keeping your body functioning optimally.

Dietary sources of magnesium include nuts, leafy greens, legumes, and seeds

Adequate magnesium intake has been linked to a reduced risk of heart disease, type 2 diabetes, and other conditions.

Taking a supplement can help you meet your daily needs if you don’t get enough of this important nutrient from food alone. Side effects are unlikely at doses below 350 mg per day.

If you’re interested in trying a supplement, speak to your healthcare provider first and choose a product that has been tested by a third party, such as U.S. Pharmacopeia.

Magnesium is widely available at health stores and online.