Magnesium is an essential nutrient, meaning it’s not produced by the body and needs to come from the diet (or supplements). It has become a nutrient of interest for its health-promoting benefits. Getting adequate amounts of magnesium in your diet could yield positive results since magnesium supports many fundamental body processes. When looking for ways to improve your health with magnesium, focus on areas of use that have the most research.

1. Can Treat Constipation

Magnesium works as an osmotic agent that causes the small intestine to absorb more water. This softens the stool and increases peristalsis (movement through the intestines).

A recent review of therapies used to treat chronic constipation found moderate evidence to support the use of magnesium-containing products.

The following are a few options available for magnesium use to treat constipation:

• Magnesium oxide: Magnesium oxide is a commonly used laxative and is available as a capsule or tablet.
• Magnesium citrate: Magnesium citrate is available in a powder and liquid form but is known as a “rescue” option because of its potency (magnesium citrate in high doses is what is prescribed for colonoscopy prep).
• Magnesium glycinate: Magnesium glycinate is available as a powder, gummy, or tablet.

The American Gastroenterological Association has recommended magnesium oxide, among several other treatments, for chronic idiopathic constipation.

The use of magnesium for constipation should be discussed with your primary healthcare provider.

2. May Help Control Blood Sugar

Magnesium plays a role in insulin secretion, which is the process of insulin being released from the pancreas into the bloodstream in response to elevated blood sugar. Insulin is the hormone that controls blood sugar levels. People with diabetes have increased urinary losses of magnesium, which may impair insulin secretion.

Low levels of magnesium correlate with insulin resistance. A few studies have also found a correlation between magnesium status and diabetes risk, as follows:

• One meta-analysis found that a 100 milligram (mg) per day increase in magnesium intake reduced the risk of diabetes by 15%.
• Another meta-analysis found an inverse relationship between magnesium intake from food and diabetes risk. This means the more magnesium in the diet, the lower the risk of diabetes.

There are conflicting results in clinical trials evaluating the effects of magnesium supplementation compared to placebo, an ineffective substance given to people in a control group. In these studies, magnesium supplementation compared to placebo has:

• Improved glucose levels in people with diabetes
• Improved markers of insulin sensitivity (the body’s ability to respond to insulin) in people at risk of diabetes. However, the studies included in the meta-analysis were all short-term studies, and the improvements were modest. More long-term research is needed.
• Reduced hemoglobin A1c levels, or a person’s average blood sugar levels over a 3-month period.

Other studies have found that magnesium supplementation did not affect glucose control.

3. May Lower Blood Pressure

Magnesium may help reduce blood pressure, but research has only demonstrated modest effects:

• One meta-analysis found a drop in diastolic blood pressure (the bottom number) of 2 millimeters of mercury (mm Hg, the standard blood pressure measurement)
• Another meta-analysis found a 3 to 4 mm Hg reduction in systolic blood pressure (the top number, measuring the force produced by the heart when it beats and pushes blood out to the body) and 2 to 3 mm Hg in diastolic blood pressure (the bottom number, measuring the force between beats).
• Similar modest reductions in blood pressure were also noted in studies of people with type 2 diabetes.

The Food and Drug Administration (FDA) approved a qualified health claim regarding magnesium and blood pressure, indicating that diets containing adequate magnesium amounts may benefit blood pressure. However, the evidence is still inconsistent and inconclusive.

To benefit blood pressure, foods must contain 84 mg of magnesium per serving, and supplements should have no more than 350 mg.

4. May Improve Heart Health

Magnesium benefits for heart health seen in studies included:

The research on magnesium for heart health has shown a correlation between higher magnesium intake and reduced disease risk. The use of magnesium supplements for primary prevention has shown modest benefits, and more research in large clinical trials is needed.

5. Supports Bone Health

Magnesium is involved with bone formation. People with higher magnesium intakes tend to have better bone mineral density. Additionally, women with osteoporosis—a bone disease that weakens bones due to decreased bone mass and bone mineral density—are more likely to have low magnesium levels.

In one short-term study, magnesium supplementation resulted in reduced bone turnover.

Having a diet that includes an adequate amount of magnesium is essential to support bone health. However, more research is needed about the role of supplements in osteoporosis prevention.

6. May Prevent Migraines

People who suffer migraines tend to have lower levels of magnesium. Research has found that magnesium may help prevent migraines. Some of the findings include:

• Some studies suggest that 600 mg of magnesium (compared to a placebo), or 300 mg of magnesium twice daily, can modestly reduce migraine frequency.
• Intravenous (IV) magnesium sulfate can reduce acute migraine attacks.
• Oral magnesium can reduce the frequency and intensity of migraines.

In a review, the American Academy of Neurology determined that magnesium is “probably effective” for migraine prevention. However, the amounts of magnesium used in some of these studies were almost twice the tolerable upper limit recommended for magnesium. More research is needed before any clinical recommendations can be made.

What Does Magnesium Do in the Body?

Magnesium has several functions and plays a role in many processes in the human body, including:

• Blood pressure control: Magnesium helps regulate our blood pressure.
• Bone formation and structure: About 50% to 60% magnesium is found in the bone.
• Energy production: Magnesium is required for glycolysis and energy production (glycolysis is the pathway in which energy is formed from the breakdown of glucose)
• Glucose control: Magnesium is needed for the enzymatic reactions that work to manage glucose levels.
• Heart rhythm: Magnesium is needed to transport potassium and calcium across cell membranes and maintain normal heart rhythms. Magnesium deficiency can disrupt normal levels of potassium and calcium.
• Muscle and nerve function: Magnesium is needed for some of the enzyme systems that regulate muscle and nerve function
• Protein production: Magnesium is needed for enzymatic reactions involved in protein synthesis.

Does Magnesium Oil Have Benefits?

Magnesium oil is a combination of magnesium chloride with water. Technically, it is not an oil but has an oily feel to the liquid. Magnesium oil is marketed as a topical solution with several health benefits, including reducing inflammation and improving sleep.

However, there is very little scientific evidence that magnesium oil provides health benefits. Two small studies found that people with fibromyalgia using transdermal magnesium chloride reported improved symptoms.

Similar results were demonstrated in people with peripheral neuropathy in a separate study. These results are preliminary, as there was no control (placebo) group for comparison. Further research is needed.

How to Get Enough

The Food and Nutrition Board has set a recommended dietary allowance (RDA) for magnesium:

• Adult females: 310–320 mg daily
• Adult males: 400–420 mg daily
• Pregnant people: 350–360 mg daily
• Breastfeeding people: 310–320 mg daily

According to recent data, most Americans do not consume the recommended amounts of magnesium. People following more plant-based or vegetarian diets have higher magnesium intake than those following meat-based diets.

Food Sources

The following foods are good sources of magnesium:

• Nuts and seeds: Pumpkin seeds, chia seeds, almonds, cashews, peanut butter
• Vegetables and fruits: Spinach, carrot, broccoli, banana, apple, avocado
• Legumes and beans: Black beans, edamame, kidney beans
• Dairy: Milk, soy milk, and yogurt
• Grains: Rice, potato, oatmeal, whole wheat bread, some cereals fortified with magnesium
• Fish: Salmon and halibut
• Meat and poultry: Chicken and lean ground beef

Supplement Sources

There are several different forms of magnesium supplements. They are often sold as compounds, such as:

The supplement facts label should include the amount of elemental magnesium, not the compound. Some small studies have suggested better absorption of magnesium with aspartate, chloride, citrate, or lactate compounds.

How Much Magnesium Is Too Much?

Most healthy people can excrete any excess magnesium the body does not need through urine. Therefore, high amounts of magnesium in foods are not a problem for most healthy people. However, high doses of magnesium supplements can lead to abdominal cramping and diarrhea.

While magnesium toxicity is rare, there have been reports of death from very high doses of magnesium. Therefore, a tolerable upper limit (UL) of 350 mg daily for adults has been established.

Summary

Magnesium is an essential nutrient with several important roles in the body. Including foods that are good sources of magnesium is recommended. Those who do not get enough magnesium in their diet should discuss supplementation with their healthcare provider. There are many health claims related to magnesium supplementation, but the research does not support all of them.