Low magnesium level is a condition in which the amount of magnesium in the blood is lower than normal. The medical name of this condition is hypomagnesemia.
Every organ in the body, especially the heart, muscles, and kidneys, needs the mineral magnesium. It also contributes to the makeup of teeth and bones. Magnesium is needed for many functions in the body, including the physical and chemical processes in the body that convert or use energy (metabolism).
When the level of magnesium in the body drops below normal, symptoms of low magnesium may develop.
Common causes of low magnesium include:
- Alcohol use
- Burns that affect a large area of the body
- Chronic diarrhea
- Excessive urination (polyuria), such as in uncontrolled diabetes and during recovery from acute kidney failure
- High blood calcium level (hypercalcemia)
- Hyperaldosteronism (disorder in which the adrenal gland releases too much of the hormone aldosterone into the blood)
- Malabsorption syndromes, such as celiac disease and inflammatory bowel disease
- Medicines including amphotericin, cisplatin, cyclosporine, diuretics, proton pump inhibitors, and aminoglycoside antibiotics
Common symptoms include:
- Abnormal eye movements (nystagmus)
- Muscle spasms or cramps
- Muscle weakness
Exams and Tests
Your health care provider will do a physical exam and ask about your symptoms.
Tests that may be ordered include an electrocardiogram (ECG).
A blood test will be ordered to check your magnesium level. Normal range is 1.3 to 2.1 mEq/L (0.65 to 1.05 mmol/L).
Other blood and urine tests that may be done include:
Treatment depends on the type of low magnesium problem and may include:
- Fluids given through a vein (IV)
- Magnesium by mouth or through a vein
- Medicines to relieve symptoms
Outcome depends on the condition that is causing the problem.
Untreated, this condition can lead to:
- Cardiac arrest
- Respiratory arrest
When to Contact a Medical Professional
When your body's magnesium level drops too much, it can be a life-threatening emergency. Call your provider right away if you have symptoms of this condition.
Treating the condition that is causing low magnesium can help.
If you play sports or do other vigorous activity, drink fluids such as sports drinks that contain electrolytes to keep your magnesium level in a healthy range.
Low blood magnesium; Magnesium - low; Hypomagnesemia
Pfennig CL, Slovis CM. Electrolyte disorders. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 125.
Smogorzewski MJ, Stubbs JR, Yu ASL. Disorders of calcium, magnesium, and phosphate balance. In: Skorecki K, Chertow GM, Marsden PA, Taal MW, Yu ASL, eds. Brenner and Rector's The Kidney. 10th ed. Philadelphia, PA: Elsevier; 2016:chap 19.
Review Date 5/21/2017
Updated by: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.