Magnesium Deficiency and Magnesium Supplements

Magnesium is found abundantly in the body – mostly in the bones (50%) and the rest in the cells of organs and tissues. Although blood contains only 1% of magnesium, the body tries hard to keep this level constant since magnesium is required for 300 and more biochemical reactions. 

Causes for magnesium deficiency

Hypomagnesemia or magnesium deficiency results due to poor absorption, inadequate intake of magnesium, specific drugs (furosemide), increased excretion because of hypercalcemia. Hypomagnesemia is treated with magnesium replacement.  

The Recommended Dietary Allowances of magnesium (National Academy of Sciences) is 320mg for women and 420mg for men. Apart from magnesium-rich foods and water, magnesium supplements must not be taken in excess of 350mg/day.  The following

Recommended Dosage of Magnesium

groups of people may suffer from hypomagnesemia.

  • Diabetics whose condition is badly controlled can suffer from deficiency since excess is lost in urine due to hyperglycemia.
  • Alcoholics suffer from low blood sugar levels. Around 90% of those suffering from alcohol withdrawal symptoms also suffer from magnesium deficiency. Their intake of a balanced diet is also minimal and this results in various deficiencies.
  • Medications like antibiotics, diuretics and anti-neoplastic medication needed for cancer treatment and steroids can all result in magnesium deficiency.
  • Elderly people whose food intake is reduced due to age can also suffer from deficiency. Added to this is the fact that due to age, their absorption levels of magnesium decreases and renal excretion increases. Senior citizens may also be on medications that interact with magnesium. All these reasons place the elderly in the high risk category and they need to take more of dietary magnesium.
  • Malabsorption Diseases such as gluten-sensitive enteropathy, Crohn’s disease and regional enteritis, those who have had intestinal surgery, can lose excessive amounts of magnesium through fat malabsorption and diarrhea.
  • Low levels of potassium (Hypokalemia) and calcium (Hypocalcemia) are two main causes for magnesium deficiency. 
  • Medical conditions such as irritable bowel syndrome, pancreatitis, ulcerative colitis, and hyperthyroidism can all result in magnesium deficiency.  
  • GI losses due to chronic diarrhea, steatorrhea and small bowel bypass can cause low levels of magnesiumRecommended magnesium dosage
  • Pregnant women suffer from certain abnormalities like eclampsia and pre-eclampsia that can cause a deficiency. Lactating mothers are also at risk.
  • Primary renal losses due to Gitelman’s syndrome – a rare disorder – can cause excessive excretion of magnesium.
  • Secondary renal losses occur when the parathyroid tumor is removed, due to thiazide and loop diuretics, hypercalcemia, diabetic ketoacidosis and hypersecretion of aldosterone. 
  • Stress: Those under severe stress can lose much of the body’s store of magnesium.
  • Other causes

    • Excessive consumption of salt, soda or coffee
    • Excessive sweating
    • Heavy menstrual periods
    • Burns

Symptoms of magnesium deficiency

Early symptoms of magnesium deficiency are:

  • Nausea
  • Loss of appetite
  • Vomiting
  • Weakness fatigue
  • Apathy
  • Anorexia
  • Fatigue
  • Muscle twitching
  • Reduced learning ability
  • Poor memory
  • Insomnia
  • Irritability

As the deficiency worsens, people can show other symptoms such as:

  • Numbness
  • Muscle contractions
  • Tingling
  • Seizures
  • Cramps
  • Abnormal heart rhythms
  • Heart changes
  • Personality changes
  • Coronary spasms

Severe deficiency results in:

  • Hypocalcemia (low levels of calcium)
  • Hypokalemia (low levels of potassium)
  • Delirium
  • Increased muscle contractions
  • Hallucinations
  • NumbnessMagnesium  Deficiency and Magnesium Supplements

Cravings for chocolate are considered a sure sign of magnesium deficiency for chocolate has rich sources of magnesium.  A physician needs to evaluate these symptoms carefully for they are similar to other medical conditions. Only after appropriate tests can it be ascertained that a person is suffering from magnesium deficiency.

Diagnosis of magnesium deficiency

When a patient comes with some of the above symptoms, serum magnesium concentration (<1.4 mEq/L or < 0.70 mmol/L) will reveal if they are deficient. Some patients can reveal symptoms of increased levels of potassium excretion in the urine and even metabolic alkalosis. Doctors will also consider magnesium deficiency in patients with unexplained refractory hypokalemia or hypocalcemia.

Magnesium Supplements

Recommended magnesium supplements include magnesium gluconate, magnesium citrate and magnesium lactate. All these three forms are easily absorbed by the body. There are also time release supplements that can be absorbed easily. Magnesium can also be absorbed through the skin, used as an antacid or laxative (magnesium hydroxide), added to baths, or taken orally as a multivitamin (magnesium sulfate).

IM magnesium sulfate and IV magnesium are given to patients who suffer from serious symptoms of hypomagnesemia or who cannot tolerate oral supplements or medications.

Some magnesium supplements are available as over-the-counter medication while others require a prescription. Capsules, powders for suspensions, liquid, extended release tablets, liquid filled capsules, and enteric coated tablets are some of the forms of magnesium supplements available. 

Precautions while taking magnesium supplements

As with all dietary supplements, care must be taken to make sure you take any form of magnesium only after consulting a doctor. There are certain categories of people who must be careful. Those with kidney and heart diseases can only take magnesium supplements under medical guidance. People can overdose on magnesium when they ingest large quantities of milk of magnesia for digestive purposes or when they take Epsom salts as a tonic or laxative.

Common side effects of excessive magnesium are diarrhea and upset stomach. Dangerously high levels of magnesium can lead to problems such as:

  • Nausea
  • Very low blood pressure
  • Vomiting
  • Slow heart rate
  • Confusion
  • Coma
  • Respiratory paralysis
  • Cardiac arrhythmia
  • Cardiac arrest

Those who suffer from impaired functioning of the kidneys must be particularly careful for they can easily accumulate excess magnesium in the body. Left unchecked, this can be very dangerous. 

Usually those who get their daily requirement of magnesium from foods do not suffer from an excess. It is those on supplements, whose magnesium levels can shoot up.  


A balanced and varied diet rich in magnesium and other vital nutrients help promote good health. If your food lacks magnesium or if you suffer from some illness that causes a deficiency, make sure you take the right magnesium supplement.