Health Benefits of Magnesium Oxide

Medically Reviewed by Dany Paul Baby, MD on November 27, 2022
3 min read

Magnesium is an important macronutrient, and it is the fourth most abundant positively-charged ion in the body. It is one of the electrolytes that cause muscles to contract, and it helps regulate your nervous system, blood sugar levels, and blood pressure. Your body needs it to complete more than 300 processes involving enzymes and proteins. Sufficient magnesium can usually be obtained through a normal, healthy diet, but low levels of magnesium can lead to serious problems.

There are at least 10 chemical compounds that contain magnesium and can be used as health supplements. Each of these is better suited for some uses than for others. Magnesium oxide is best used for digestive problems and heartburn. Magnesium oxide can also be used to supplement magnesium levels in the body, but it may not work as well as other magnesium compounds that are more readily absorbed into the bloodstream, including those you can get naturally from foods.

Magnesium oxide, often available in capsule form, is commonly used to help a number of concerns, ranging from simple low magnesium levels to more specific concerns, like the following:

Relief of Indigestion and Heartburn

Magnesium oxide may be used as an antacid to relieve indigestion and heartburn.

Relief from Constipation and Irregularity

Magnesium oxide causes the intestines to release water into the stool, which softens the stool and relieves constipation and irregularity. A dose of 250 milligrams can be repeated every 12 hours until you find relief.

Relief from Migraine

Studies have shown that patients with migraine, including cluster headaches and menstrual migraine, often have low levels of magnesium, and taking supplements like magnesium oxide may be helpful. Studies suggest that magnesium ions provided by magnesium oxide interrupt the brain signals that may cause migraine. A dose of 400–500 milligrams per day may be required to be effective. This dose may also cause diarrhea as a side effect, but this can usually be controlled by starting with a smaller dose.

Other Health Benefits

Magnesium offers many other health benefits, but magnesium oxide is not the best source for these benefits. Magnesium oxide has difficulty dissolving in water and is not absorbed into bodily tissues as easily as water-soluble magnesium salts, such as magnesium citrate, magnesium chloride, magnesium lactate, or magnesium malate.

Magnesium oxide is widely used and generally recognized as safe, but it can come with some uncomfortable side effects, such as:


Because of the same properties that make it a great laxative, even when you’re using it for other health benefits, magnesium oxide can cause cramping or diarrhea.

Flu-like Symptoms

While this is usually not of concern when magnesium oxide is used as a supplement, it is good to be aware that as an industrial chemical, magnesium oxide is recognized as a hazardous substance. Inhalation and prolonged exposure to large amounts of magnesium oxide can irritate the eyes and nose, and can cause flu-like symptoms in some people.

Magnesium is readily available from food, and you can get a good amount from leafy vegetables, nuts, seeds and whole grains. An easy way to remember this is to associate magnesium with fiber. In most cases, foods that are good sources of fiber are also high in magnesium.

The Recommended Dietary Allowance (RDA) for magnesium is 400-420 mg per day for adult men, and 310-320 mg per day for adult women. Women who are pregnant may increase this amount to 350-360 mg per day.

If you are taking magnesium oxide for nutritional purposes, most brands recommend using tablets or capsules, and they suggest taking only 250 milligrams per day. The rest of your magnesium can be obtained from the foods you are eating.

Take capsules or tablets with a full 8 ounce glass of water and with a regular meal.

However, if you are using magnesium as a laxative to relieve occasional constipation or irregularity, you might take it in liquid form, and higher doses may be suggested. Follow the label directions, and do not use it as a laxative for more than 1 week without consulting a doctor.

As with all supplements, you should check with your doctor if you are considering adding magnesium citrate supplements to your diet.