Magnesium Deficiency

Medically Reviewed By William C. Lloyd III, MD, FACS

What is magnesium deficiency?

Magnesium is the fourth most common mineral in the human body, after calcium, potassium and sodium. The body needs magnesium for a wide range of processes, including muscle and nerve function, controlling blood sugar levels, and maintaining healthy blood pressure. Magnesium also helps the body use other nutrients, like vitamin D.

The recommended amount of magnesium varies according to age, but most healthy adults should have between 310 to 320 mg of magnesium per day (women) or 400 to 420 mg per day (men). Low levels of magnesium in the body, known as magnesium deficiency or hypomagnesemia, can result from someone not consuming enough magnesium, from the intestines absorbing too little magnesium, or from losing too much magnesium through the urine.

Low magnesium levels affect up to half of adults in the United States. Treating magnesium deficiency depends on identifying and addressing the underlying cause.

Symptoms of magnesium deficiency include nausea and vomiting, fatigue, muscle contractions, and weakness. Extreme or severe magnesium deficiency is a medical emergency and can cause life-threatening heart rhythms, called arrhythmias. Seek emergency care (call 911) if you or someone you are with experiences rapid or irregular heart rate, difficulty breathing, or sudden muscle weakness.

What are the symptoms of magnesium deficiency?

The signs of magnesium deficiency can be subtle at first and may be mistaken as symptoms of other common conditions. Talk to your doctor if you notice any of these symptoms so you can more quickly get an accurate diagnosis.

Common symptoms of magnesium deficiency

The most common symptoms of magnesium deficiency are:

  • Fatigue
  • Weakness

Serious symptoms that could occur include:

  • Migraine

If you have a combination of any of the above symptoms, speak with your healthcare provider about your symptoms and your concerns. Detecting magnesium deficiency early can help diagnose a condition that is causing it or allow you to make lifestyle changes or undergo treatment to bring the magnesium levels back up to normal.

What causes magnesium deficiency?

Magnesium deficiency can have several causes ranging from not consuming enough foods with magnesium to losing magnesium due to illness.

Gastrointestinal conditions

Certain GI conditions can affect the body’s ability to take in magnesium, often due to chronic diarrhea or lack of absorption in the intestinal tract. Gastrointestinal conditions that can cause magnesium deficiency include:

  • Crohn’s disease

Type 2 diabetes

People with type 2 diabetes experience chronic elevated blood glucose. The kidneys fail to filter the excess glucose, allowing the glucose to enter the urine. This redirects more water to the urine. This can lead to excessive urine output, which can deplete the body’s magnesium levels.

Alcohol dependence

The effects of alcohol dependence can include gastrointestinal issues, kidney damage, liver disease, and poor nutrition—all of which can lead to lower absorption of magnesium.

Other causes of magnesium deficiency

Magnesium deficiency can also occur as a result of:

  • Age
  • Breastfeeding
  • Lack of magnesium intake through diet
  • Medications that increase urine output, such as diuretics
  • Serious or severe burns over a large part of the body

What are the risk factors for magnesium deficiency?

A number of factors increase the risk of developing magnesium deficiency. Not all people with risk factors will have low magnesium levels, but the condition does affect about half of all adults in the U.S.

Risk factors for magnesium deficiency include:

  • Age. As people get older, the body’s ability to absorb nutrients like magnesium naturally decreases.
  • Alcohol dependence
  • Gastrointestinal conditions, including Crohn’s disease and celiac disease, that affect absorption of nutrients
  • Pregnancy or breastfeeding, which can increase the body’s need for magnesium
  • Poor diet
  • Taking medication that causes diarrhea or increased urine output, such as a diuretic

Reducing your risk of magnesium deficiency

You may be able to lower your risk of magnesium deficiency by:

  • Eating a healthy magnesium-rich diet
  • Managing chronic illnesses
  • Switching medications under the pharmacist’s or doctor’s supervision
  • Taking magnesium supplements

Speak with your healthcare provider if you think you may be at risk of magnesium deficiency and to discuss what steps you can take to lower your risk.

What are the diet and nutrition tips for magnesium deficiency?

Many foods are naturally high in magnesium, and a healthy person eating a balanced diet should be able to consume the recommended daily amount.

Foods that contain magnesium include:

  • Black beans and kidney beans
  • Cooked spinach, broccoli, carrots 
  • Dairy foods, such as low-fat milk and low-fat yogurt
  • Dark chocolate
  • Lean beef and poultry
  • Nuts, such as almonds, peanuts and cashews
  • Oatmeal
  • Peanut butter
  • Potatoes (with skin)
  • Rice
  • Salmon

If in doubt about what type of foods are best and how to prepare them, speak with your doctor’s office about meeting with a dietitian, who may provide you with ideas on how to maximize your nutrients through your diet. The U.S. Department of Agriculture’s My Plate program and the government’s Dietary Guidelines for Americans Trusted Source Dietary Guidelines for Americans (USDA) Governmental authority Go to source also provide guidance on healthy dietary choices.

While it is not usually possible to get too much magnesium from diet alone, it is possible to get too much through supplements. Always speak with your doctor before taking any new vitamins or supplements.

What are some conditions related to magnesium deficiency?

People who are magnesium deficient have a high risk of also being deficient in vitamin D, the so-called sunshine vitamin. The body needs magnesium in order to activate vitamin D, whether it is absorbed through the sun or through food.

Without magnesium, vitamin D cannot work with calcium to help strengthen bones and contribute to heart and metabolic health. As a result, people with magnesium deficiency can develop osteoporosis and heart disease.

How do doctors diagnose magnesium deficiency?

To diagnose your condition, your doctor or licensed healthcare practitioner will ask you several questions related to your symptoms and diet. After a physical exam, your doctor may recommend some of these tests:

  • Blood tests to examine your magnesium and other nutrient levels
  • Urine test, to determine if too much magnesium is being excreted

If there is concern about other conditions that may be causing the deficiency, your doctor may test you for conditions that could affect nutrient absorption, such as diabetes or kidney disease. If you may have had magnesium deficiency for a considerable length of time, you may also undergo a bone scan to measure the strength of your bones.

What are the treatments for magnesium deficiency?

Mild magnesium deficiency can often be addressed by increasing consumption of magnesium through diet or with magnesium supplements, as recommended by your doctor. If magnesium deficiency is being caused by an underlying condition, treatment and management of that condition will in turn help improve magnesium levels.

Treatment for severe magnesium deficiency usually involves oral (by mouth) magnesium salts or an intravenous or intramuscular injection of magnesium. Side effects from these treatments may be bothersome, but can often be managed until magnesium levels reach the needed levels.

What are the potential complications of magnesium deficiency?

Because magnesium plays a vital role in body health, continued magnesium deficiency could lead to serious complications, such as:

  • Cardiac arrest, due to decreased cardiac muscle function
  • High blood pressure
  • Osteoporosis, due to because of the inability of for the bones to absorb the necessary nutrients
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  2. Feeling Fatigued? Could It Be Magnesium Deficiency? (And If So, What to Do About It!), Cleveland Clinic. https://health.clevelandclinic.org/feeling-fatigued-could-it-be-magnesium-deficiency-and-if-so-what-to-do-about-it/
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  8. Uwitonze A, Razzaque MS. Role of Magnesium in Vitamin D Activation and Function. The Journal of the American Osteopathic Association, 2018; 118 (3): 181 https://sci-hub.se/https://doi.org/10.7556/jaoa.2018.037
  9. Hypomagnesemia. Merck Manual. https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hypomagnesemia
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jun 24
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