What Is Magnesium Deficiency?

Magnesium deficiency, or hypomagnesemia, occurs when magnesium levels in your body are below what is needed to function normally. Magnesium is one of several electrically charged minerals, called electrolytes, that the body uses to regulate body functions like heart rhythm, blood pressure, and brain function.

Hypomagnesemia occurs when a disease, medication, or nutritional problem affects the body’s absorption or elimination of magnesium. Symptoms of magnesium deficiency range from nausea, fatigue, and muscle cramps to abnormal heart rhythms, seizures, and coma.

This article explains the causes and symptoms of magnesium deficiency as well as how the condition is diagnosed, treated, and prevented.

Health Conditions Associated with Magnesium Deficiency

Verywell / Ellen Lindner

Why Magnesium Is Important

Magnesium is an essential mineral that the body needs to stay healthy. An essential mineral is one that is vital for maintaining the body’s health and can only be obtained from diet or supplements.

Magnesium is absorbed in the stomach and small intestines. It then works with other electrolytes, such as calcium, potassium, and sodium, to regulate nerve and muscle function, balance fluids, maintain blood pressure and acidity, and rebuild damaged tissues.

Magnesium plays a central vital role in:

The kidneys are responsible for maintaining the optimal levels of magnesium in the body. They do so by either increasing or decreasing how much magnesium is eliminated in urine.

Causes of Magnesium Deficiency

Magnesium deficiency occurs when magnesium levels drop below the expected normal range,

Severe magnesium deficiency is uncommon in otherwise healthy people. It mostly occurs when the intake of magnesium is exceptionally low, the absorption of magnesium is impaired, or the elimination of magnesium from the body is increased.

Common causes inclcude:

  • Alcohol use disorder: Alcohol overuse can lead to poor nutrition, problems with digestion, and kidney and liver dysfunction—all of which impact magnesium absorption and excretion.
  • Celiac disease: This hereditary disorder caused by an immune reaction to gluten can alter the absorption and elimination of many essential minerals, including magnesium.
  • Cystic fibrosis: This genetic disorder causes the excessive production of mucus in the intestines, blocking the absorption of minerals like magnesium.
  • Diabetes: When uncontrolled, type 1 and type 2 diabetes both cause excessive urination which promotes the elimination of magnesium.
  • Diarrhea: Severe (acute) or persistent (chronic) diarrhea eliminates large amounts of magnesium and other nutrients.
  • Inflammatory bowel disease: This chronic inflammatory disorder is characterized by the malabsorption of many nutrients, including magnesium.
  • Gastric bypass surgery: This weight loss surgery reduces the size of the stomach and, in turn, the area of tissues where magnesium can be absorbed.
  • Kidney tubular disorders: These conditions affect parts of the kidneys, called tubules, that normally retrieve magnesium from the blood.
  • Medications: Examples include diuretics that promote magnesium elimination or proton pump inhibitors that block magnesium absorption. Some antibiotics, immunosuppressants, and chemotherapy drugs can do the same.
  • Pancreatitis: The sudden inflammation of the pancreas can cause malabsorption and depletion of nutrients such as magnesium.
  • Starvation: A severe lack of nutrition can result in low magnesium levels.

About Electrolyte Imbalance

High or low levels of one electrolyte will almost invariably raise or lower others, causing an electrolyte imbalance. Electrolyte imbalances such as hypocalcemia (low calcium) or hypokalemia (low potassium levels) commonly occur with severe magnesium deficiency.

At-Risk Groups

Magnesium deficiency is relatively uncommon but certain people are at greater risk than others, including:

  • Older adults: People over 60 often have smaller appetites or take medications that interfere with magnesium absorption/retention. Aging-related changes in the digestive tract can also affect magnesium absorption.
  • Infants and toddlers: Younger children are vulnerable to dehydration due to their smaller body size and faster metabolism. This causes them to replace water and electrolytes at faster rates than adults.
  • Critically ill people: People who cannot take food by mouth and must receive all their nutrition intravenously (through a vein) are prone to multiple nutritional deficiencies.

Signs and Symptoms of Low Magnesium

Magnesium deficiency may be largely asymptomatic (without symptoms) until levels drop significantly. There may also be generalized, non-specific symptoms that you can easily mistake for other conditions, such as being overly tired.

Common symptoms of low magnesium include:

  • Loss of appetite 
  • Nausea or vomiting 
  • Fatigue 
  • Weakness
  • Muscle spasms
  • Stiffness

As magnesium deficiency worsens, the following symptoms can develop:

  • Tingling or numbness in the hands or feet
  • Muscle cramps or spasms 
  • Tremors
  • Abnormal eye movements (nystagmus)
  • Personality or behavioral changes
  • Abnormal heart rhythms (arrhythmia)
  • Seizures
  • Coma

How Serious Is Low Magnesium?

Studies have shown magnesium deficiency can lead to the onset or worsening of the following diseases: 

Testing and Diagnosis

If you are suspected of having hypomagnesemia, your healthcare provider will start by reviewing your symptoms and medical history and performing a physical exam, including your vital signs.

Magnesium deficiency is diagnosed with a blood test. The results of the test are then compared to a reference range of values that describe high and low values for magnesium that are considered normal.

The reference range for magnesium can vary by the lab and population but is generally described as follows:

  • Adults: 1.8 to 2.6 milligrams per deciliter (mg/dL)
  • Children: 1.7 to 2.2 mg/dL

For most people, however, symptoms don't occur until levels drop below 1.2 mg/dL.

Based on other findings, other tests may be ordered to characterize the deficiency or determine its impact on the body, including:

  • Comprehensive metabolic panel (CMP): This is a panel of 14 different tests that check for key factors in your blood, including electrolytes like potassium, sodium, and calcium.
  • Urinalysis: This measures components in your urine to detect kidney dysfunction. A 24-hour urinalysis may be used to measure potassium collected over 24 hours.
  • Electrocardiogram (ECG): This is a device that measures the electrical activity of the heart in order to diagnose heart problems like arrhythmia.


Prevention starts with the dietary or nutritional intake of magnesium through foods, including nuts, seeds, beans, whole grains, and fortified foods.

Foods rich in magnesium include:

  • Pumpkin seeds
  • Chia seeds
  • Almonds
  • Spinach
  • Cashews
  • Peanuts
  • Soymilk
  • Black beans
  • Edamame
  • Peanut butter
  • Baked potato
  • Plain low-fat yogurt
  • Fortified breakfast cereals
  • Kidney beans
  • Banana
  • Salmon
  • Halibut
  • Wholewheat bread
  • Avocado
  • Chicken breast
  • Ground beef
  • Broccoli
  • White rice
  • Carrots

Do I Need to Take a Magnesium Supplement?

Most people get more than enough magnesium from foods and do not need magnesium supplements. On the flip side, the excessive use of magnesium supplements can be toxic and has been known on rare occasions to cause respiratory paralysis and cardiac arrest when taken at doses of over 5,000 milligrams per day.


The goal of treatment is to manage the underlying causes of magnesium deficiency as well as replenish it through oral or intravenous (IV) supplements. 

Magnesium Supplements

Oral magnesium is used for those with mild hypomagnesemia and comes in pill, powder, and liquid form. There are also different types, including magnesium oxide, magnesium citrate, magnesium gluconate, and magnesium chloride. Liquids or powders that dissolve well in fluids often have better intestinal absorption rates than pills. 

Intravenous Magnesium

When a person has a severe magnesium deficiency, they may need an intravenous magnesium infusion. This is usually performed in a hospital and needs to be monitored carefully by a healthcare professional.


Magnesium deficiency due to low dietary intake in otherwise-healthy people is uncommon. However, it’s important to include leafy green vegetables, nuts, seeds, and whole grains in your diet to prevent low levels of nutrients like magnesium.  

Your doctor may suggest oral supplements to treat mild magnesium deficiency. Be aware of the side effects of oral magnesium, which include diarrhea, nausea, and vomiting. 

Tell your doctor about all the medications you take, including supplements and over-the-counter medications such as laxatives and antacids. Drugs and supplements can sometimes interfere with each other and disrupt the balance in the body.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Office of Dietary Supplements. Magnesium.

  2. Ahmed F, Mohammed A. Magnesium: the forgotten electrolyte—a review on hypomagnesemia. Med Sci. 2019;7(4):56. doi:10.3390/medsci7040056

  3. Medline Plus. Fluid and electrolyte balance.

By Brandi Jones, MSN-ED RN-BC
Brandi is a nurse and the owner of Brandi Jones LLC. She specializes in health and wellness writing including blogs, articles, and education.