Magnesium: ‘The forgotten essential element’

Magnesium (Mg+) is an essential mineral which is a cofactor for over 300 enzymatic reactions for protein synthesis, muscle contractions, nerve function, blood pressure, hormone-binding, etc.  It is the most abundant mineral in our bodies after calcium, potassium and sodium.  It has an overall calming effect. 

Magnesium in food has declined by 25-80% compared to the 1950s as our soil is getting depleted due to farming practices. 

This essential element is critical for the conversion of 25-hydroxy vitamin D (calcifediol) to 1,25 dihydroxy vitamin D (calcitriol), which is the active form of Vitamin D.  1,25 dihydroxy vitamin D in turn will help with the absorption of Mg+. 

The half-life of Mg+ is ~1000 hours.  Despite this long half-life it is recommended that oral intake from dietary sources or supplementation occurs every day. 

According to Health Canada the recommended dietary allowance is 420 mg of elemental magnesium a day.  Most people will require significantly more than that due to pre-existing deficiency or inadequate dietary intake.  This is why supplementation is often necessary.  

Signs and symptoms of magnesium deficiency 

  • Muscle cramps/spasms/tremors 
  • Sleep disturbance 
  • Fatigue/Somnolence 
  • Stress/anxiety/feeling wired 
  • High blood pressure
  • Constipation (you need Mg+ for colon motility) 
  • Cognition problems 
  • Headaches 
  • Heart palpitations 
  • Low bone density (osteopenia/osteoporosis) 
  • Asthma 

Magnesium deficiency can be more prevalent in people who: 

  • Drink caffeinated drinks or alcohol often 
  • Have low vitamin D, which aids in magnesium absorption (and vice-versa) 
  • Are uncontrolled diabetics 
  • Eat a lot of refined sugar, which causes the body to excrete magnesium through the kidneys 
  • Have some genetic disorders 
  • Are on corticosteroids 

How to test for magnesium deficiency? 

Serum magnesium is not a good indicator or magnesium levels as most of it is contained inside cells. We use RBC (red blood cell) magnesium levels to diagnose the presence and severity of a deficiency and recommend a specific supplementation regimen.  Note that this test costs $34.00 and is not covered by MSP. 

 Major dietary magnesium sources  

These include: 

  • Leafy green vegetables like spinach 
  • Squash 
  • Pumpkin seeds 
  • Nuts and seeds 
  • Legumes or beans 
  • Fish 
  • Whole grains 

Magnesium and Hypertension 

Anyone with hypertension should test their magnesium levels and optimize them. Extensive research linking low magnesium and cardiovascular disease have shown benefits, especially in lowering blood pressure.  Doses of > 600 mg elemental magnesium a day can help reduce hypertension. 

Forms of magnesium 

Absorption mainly occurs in the small intestine.  Not all forms are absorbed the same.  Some forms have side-effects and benefits compared to others.  

There are many forms available:  

  • Magnesium lactate 
  • Magnesium chloride or hydrochloride 
  • Magnesium sulfate (better known as Epsom salts.  Not recommended orally but can be added to your bath which will allow for absorption through your skin to relieve muscle cramps.  In the hospital we use it IV for medical emergencies such as severe asthma or preeclampsia) 
  • Magnesium taurate (often used for heart health, especially following a cardiac event, or for heart palpitations/arrhythmia.  Great also for  migraines, diabetes or insulin resistance) 
  • Magnesium malate (a good choice for people with fibromyalgia, chronic fatigue) 
  • Magnesium lactate 
  • Magnesium glycinate or bisglycinate (great for patients with poor sleep, anxiety and depression)  
  • Magnesium carbonate (helps neutralize the pH of the stomach, recommended in patients with acid reflux or heartburn) 
  • Magnesium citrate (laxative effects, great for constipation) 
  • Magnesium threonate or L-threonate (excellent absorption, about 90%, but a bit more pricey)

Preferred forms of magnesium 

A mixture is recommended for improved absorption, maximize benefits and to minimize unwanted side-effects such as diarrhea. 

Aim for > 650 mg and even closer to 1000 mg of elemental magnesium daily, depending on your levels and the recommendation of your physician. 

Mg+ glycinate and bisglycinate ~ 24% absorption.  Bisglycinate is preferred for its higher absorption compared to glycinate. Glycine is a precursor to GABA, which is an inhibitory (calming) neurotransmitter. Good for sleep and depression.  Also good for athletic performance and recovery.   This form is the most recommended for patients who need to replenish their Mg+ levels. 

Mg+ citrate ~ 30% absorption.  Magnesium is bound to citric acid which is an antioxidant, highly bioavailable and well-absorbed.  This particular form is recommended for patients who suffer from migraines.  It is also a natural remedy to constipation due to its laxative effects.  Watch for potential increased aluminum absorption.  

Mg+ threonate or L-threonate ~ 90%. Majority is absorbed.  Crosses the BBB (blood-brain barrier) to have effects on the brain and the nervous system. Helps with brain function, memory, anxiety, restlessness. Early research suggests cognitive benefits. 

Mg+ taurate.  Similar to Mg+ L-threonate. Crosses the BBB (blood-brain barrier).  Good for migraines, diabetes or insulin resistance. 

Mg+ sulfate. Most commonly known as Epsom salts, absorbed through the skin.  Preferable for patients who can’t tolerate oral supplementation or want to address muscular tension or cramps in particular.  

Forms that are not recommended: 

Mg+ aspartate.  This form is not recommended as it contains aspartate, a component of the neurotoxic artificial sweetener aspartame.  Moreover, aspartate is an excitatory neurotransmitter. 

Mg+ glutamate.  Should be avoided as it contains glutamic acid which is an excitatory amino acid.  It also has been linked to worsening depression or anxiety symptoms. 

Mg+ oxide.  Very low absorption despite being the most common form of magnesium available.  Since it is non-chelated, it is more difficult for the body to absorb.  Some studies also have shown that it causes inflammation of the heart membrane (pericardium). 

Recommended dosing: 

  • >650 mg and even closer to 1000 mg of elemental Mg+ twice or three times a day. 
  • Take in the evening to help with sleep. 
  • Watch for side-effects, most commonly loose stools, especially with some forms such as Mg+ citrate. 


If you would like to get your RBC magnesium level checked, and obtain personalized recommendations to optimize this essential element, make an appointment today! 



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