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    Other name(s):

    magnesium carbonate, magnesium citrate, magnesium hydroxide, magnesium oxide, magnesium sulfate

    General description

    Magnesium is an essential mineral. It helps the way that more than 300 enzymes work. It’s needed for nerve and muscle activity. It also controls the electrical and muscle activity of the heart. Magnesium is in many antacids and laxatives. It's found in many foods. Because of this, magnesium deficiency is rare.

    Magnesium is needed for many functions in the body. These include:

    • Activating enzymes that help break down carbohydrates

    • Nerve conduction

    • Helping control nerve irritability

    Magnesium helps bone and tooth enamel form. It’s needed to convert protein, carbohydrates, and lipids into energy. It also helps make protein, RNA, and DNA. Magnesium helps break down (metabolize) of many substances in the body.

    Medically valid uses

    Magnesium is used as a laxative. This is often done in the form of magnesium sulfate or magnesium citrate. Magnesium citrate is given to cleanse the bowel before taking X-rays, CT scans, or MRIs of the abdomen.

    It is used in some treatments for heartburn and upset stomach due to acid indigestion

    Magnesium is also used to prevent and treat low magnesium levels. This is called hypomagnesemia. In hospitals, magnesium is used to treat preeclampsia and eclampsia. These issues can happen in pregnancy and right after childbirth.

    Magnesium works with calcium, vitamin D, and parathyroid hormone to make healthy bone tissue and tooth enamel.

    Your healthcare provider may prescribe magnesium to treat certain heart problems. These include: 

    • Heart attack

    • Heart rhythm problems

    • Congestive heart failure

    • Digitalis poisoning

    It may also be used during cardiac surgery.

    Unsubstantiated claims

    There may be benefits that have not yet been proven through research.

    Magnesium may:

    • Help maintain health of muscles, bone, and nerve tissues

    • Help with anxiety and depression

    • Induce sleep in people with insomnia

    • Relieve premenstrual syndrome (PMS)

    • Prevent muscle cramps, muscle weakness, and fatigue

    • Prevent heart disease

    • Prevent hardening of the arteries (arteriosclerosis)

    • Prevent high triglyceride levels

    Recommended intake

    Magnesium is measured in milligrams (mg). The Recommended Dietary Allowance is RDA.



    Infants (0–6 months)

    30 mg*

    Infants (6 months to 1 year)

    75 mg*

    Children (1–3 years)

    80 mg

    Children (4–8 years)

    130 mg

    Children (9–13 years)

    240 mg

    Boys (14–18 years)

    410 mg

    Girls (14–18 years)

    360 mg

    Men (19–30 years)

    400 mg

    Women (19–30 years)

    310 mg

    Men (31 years and older)

    420 mg

    Women (31 years and older)

    320 mg

    Pregnant women (14–18 years)

    400 mg

    Pregnant women (19–30 years)

    350 mg

    Pregnant women (31 years and older)

    360 mg

    Breastfeeding women

    No change

    *Adequate Intake (AI)

    Magnesium supplements come in many forms. Each form has a different amount of magnesium. Magnesium oxide and magnesium hydroxide have the highest amounts of it. Magnesium gluconate and magnesium gluceptate have the lowest.

    Dose may be noted as the amount of magnesium. Or it may be noted as the percentage. Read the label to see how what is noted. You can learn the amount of elemental magnesium in a food. To do this, multiply the percentage of magnesium by 10. One (1) gram of magnesium oxide has 60.3% of magnesium or 603 mg.

    You should take magnesium supplements with food. This can help prevent diarrhea.

    You may need more magnesium if you have any of these:

    • Diabetes

    • A malabsorption syndrome

    • Kidney disease

    • Take water pills (diuretics) regularly

    • Having vomiting or diarrhea

    • Have burns over large areas of the body

    • Extreme athletic activity

    • Moderate-to-heavy alcohol use

    You may also need more magnesium if you are an athlete who restricts calories.

    Food source

    Nutrient content per 100 grams


    267 mg


    252 mg

    Brewer's yeast

    231 mg


    181 mg

    Peanut butter

    178 mg


    158 mg


    134 mg

    Kidney beans

    132 mg

    Dried figs

    82 mg

    Beet tops

    71 mg


    70 mg

    Lima beans

    66 mg

    Magnesium is in nearly all foods. Because of this, it’s rare to have a diet low in magnesium. Signs of deficiency may include:

    • Weakness

    • Confusion

    • Muscle tremor

    • Abnormal heart rhythm

    • Lack of coordination

    • Personality changes

    • Gastrointestinal disorders

    • Loss of appetite

    Side effects, toxicity, and interactions

    Taking too much magnesium can cause diarrhea. This is the most common side effect. It can also cause:

    • Low blood pressure (hypotension)

    • Muscle weakness

    • Nausea

    • Vomiting

    Magnesium supplements may be dangerous for some people. This includes:

    • People with kidney problems

    • People with a heart block

    Women who are pregnant or breastfeeding talk to their healthcare providers before taking any supplements.

    Magnesium is used in many antacid forms. These can cause diarrhea. Taking magnesium with food may help prevent this side effect.

    Magnesium may change the effects of some medicines. These include:

    • Bisphosphonates

    • Antibiotics

    • Diuretics

    • Proton pump inhibitors

    Tell your healthcare provider about all medicines you take before you take magnesium.

    Online Medical Reviewer: Cynthia Godsey
    Online Medical Reviewer: Diane Horowitz MD
    Online Medical Reviewer: Rita Sather RN
    Date Last Reviewed: 1/1/2019
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