Magnesium is an essential mineral for the vital functions of our body. It is one of the most abundant metal elements in the body. It is found in our diets in grain products, nuts and peanuts, red meat and vegetables. We take an average of 250-350 mg of Mg daily with diet.

Magnesium (Mg)

Magnesium is an essential mineral for the vital functions of our body. It is one of the most abundant metal elements in the body. It is found in our diets in grain products, nuts and peanuts, red meat and vegetables. We take an average of 250-350 mg of Mg daily with diet. Magnesium is an important mineral that functions in many enzymatic functions in our body. 200 mg of dietary magnesium is excreted in feces and 100 mg in urine.

While the amount of magnesium in the blood plasma is 1.7-2.7 mg/dL on average, there is approximately 20-30 g of magnesium in our body. There are also centers that express the mean plasma magnesium level as 1.4-1.7 mEq/L. About 60% of the total magnesium in our body is stored in the bones. The remainder is found mostly in muscle tissues and a small amount in intercellular spaces. Magnesium takes part in the activity of about 300 enzymes in the body. It mostly works in blood, liver and muscle tissues. Magnesium is of great importance in the growth and regeneration of cells, enzyme and coenzyme activity, protein synthesis, and strengthening of bone and muscle tissue. Magnesium is an activator of phosphatase, phosphorylase, enolase, phosphoglucomutase enzymes and is also an inhibitor of Na/K ATPase in cells.



Magnesium is also used in the treatment of hypertension, diabetes mellitus, asthma, heart rhythm disorders and some kidney diseases. In fact, it has an important role in the contraction of the heart muscle and maintaining the continuity of peripheral vascular tone by regulating the calcium movement in the smooth muscle cells. It can also be used to relieve muscle cramps and sometimes as a muscle relaxant.

Magnesium is also responsible for reaching the action centers of minerals and electrolytes, hormones and neurotransmitters. It also plays an important role in the transmission of the electrical waves of the brain. In addition, it provides the movement of many enzymes, proteins or other structures that enter and leave the cell by taking part in the membranes of the cells. For example, in magnesium deficiency, the cells’ ability to retain or release certain minerals weakens and symptoms begin to develop.

If the body cannot get enough magnesium from food, the body uses the magnesium stores in the bones. About half of the dietary magnesium is absorbed from the intestines.

Low level of magnesium in the blood (Hypomagnesemia):

A decrease in blood serum Mg level below 0.66 mmol/L (< 1.6 mg/dl) is defined as hypomagnesemia. Symptomatic hypomagnesemia is seen in patients whose serum magnesium falls below 1.2 mg/dL. If magnesium deficiency is detected, the corrected magnesium level is recalculated and other causes are investigated, and other diseases with similar clinical symptoms are also evaluated.



Magnesium deficiency is usually due to low dietary magnesium intake or excessive loss from the intestines. Some of the losses are magnesium excreted in the urine. Magnesium deficiency can be seen in 12-65% of patients treated in intensive care units.

Magnesium deficiency affects many functions in the body. Patients may experience nausea, vomiting, neurological symptoms, tetany, tremor, muscle twitches, personality disorders, and even seizures. Some patients may even experience apathy, coma, or delirium with muscle cramps. Depression, introversion, psychosis, irritable mood, mood disorders, and occasional disorientation, various ECG changes and cardiac symptoms that can go up to atrial fibrillation are other symptoms that can be seen in magnesium deficiency.

Causes of magnesium deficiency (Hypomagnesemia):

  • Redistribution
    • After IV glucose therapy
    • Correction of diabetic ketoacidosis
    • Parenteral nutrition
    • Refeeding after starvation
    • Acute pancreatitis
    • Postparathyroidectomy (hungry bone syndrome)
    • Osteoblastic metastasis (Hungry bone syndrome)
  • Extrarenal losses
    • Nasogastric losses (rarely)
    • Breast-feeding
    • Excessive sweating
    • Burns
    • Sepsis
    • Intestinal or biliary fistula
    • Excessive and prolonged diarrhea
  • Renal losses
    • Ketoacidosis
    • Salt or osmotic diuresis
    • Potassium depletion
    • Phosphorus depletion
    • Familial hypophosphatemia
    • Tubulointerstitial kidney disease
  • decreased intake
    • Alcoholism (cirrhosis) (common)
    • Insufficient intake due to malnutrition (frequent)
    • Small bowel resection
    • Malabsorption (steatorrhea)
  • Medicines
    • Diuretics
    • Aminoglycosides
    • Amphotericin B
    • Pentamidine
    • Capreomycin
    • Vitamin D poisoning
    • Alcohol and ethanol
    • Cisplatin
    • Cetuximab
    • Theophylline
    • Proton pump inhibitors
  • Congenital causes
    • TRPM6 (transent receptor potential melastatin 6) defect
    • Familial hypomagnesemia (paracellein-1 (claudin16 (CLDN16)) defect)
    • Bartter syndrome (type III Bartter syndrome)
    • Gitelman syndrome
    • Hypomagnesemia with secondary hypocalcemia (HSH)
    • Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC)
    • Autosomal dominant hypocalcemia (ADHD) with hypercalciuria
    • Isolated dominant hypomagnesemia (IDH) with hypocalciuria
    • Isolated recessive hypomagnesemia (IRH) with normocalcemia
  • Endocrinological reasons
    • Inappropriate ADH
    • Hyperthyroidism
    • Hyperparathyroidism
    • Hypercalcemic conditions
    • Primary or secondary aldosteronism

Increased level of magnesium in the blood (Hypermagnesemia):

A serum Mg level above 2.7 mg/dl in the blood is called hypermagnesemia. Symptoms such as lethargy, confusion, coma, muscle weakness, decreased deep tendon reflexes, hypotension, arrhythmia and hypoventilation are seen in patients according to the level of increase in magnesium level. These patients should also be evaluated in terms of hyperkalemia and hypercalcemia.



Severe hypermagnesemia is most commonly encountered in patients with chronic renal failure, with the intake of magnesium-containing antacids or anti-constipant drugs. In gastrointestinal diseases such as active ulcer disease, gastritis, ulcerative colitis, hypermagnesemia may develop secondary to the increase in Mg absorption.

Causes of hypermagnesemia:

  • Increase in magnesium intake
    • Eclampsia treatment
    • Antacids
    • Laxatives
    • Oral intake (drugs, often accompanied by kidney failure)
    • MgSO4 infusion (during preeclampsia & eclampsia treatment)
    • Tumor lysis syndrome
  • Decreased renal excretion
    • Acute kidney failure
    • Chronic renal failure
    • Hypovolemia
    • Addison’s disease
    • Primary hyperparathyroidism
    • Adrenal insufficiency (due to hemoconcentration)
  • Medicines
    • Cathartics
    • Laxatives
    • Enema
    • Epsom salt poisoning



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