DrG's Medisense Feature Article

Magnesium
By Ann Gerhardt, MD
October 2025
Print Version

Bottom line at the top: Magnesium is essential for human health.  Deficiency of it contributes to many chronic diseases.  Maintain adequate levels with a magnesium-rich diet described below.

Supplement makers have latched onto magnesium, an essential nutrient, as another way to make money and cure what ails us.  Yes, I’m again being cynical.  The magnesium section of store shelves in some pharmacies now exceeds the spaces for fish oil, vitamin C or vitamin D supplements, each of which proliferated for some time. 

Magnesium is an essential mineral, the only source being the diet. While it is present in every body tissue, no organ stores it to compensate for periods of dietary insufficiency.  It contributes to physiological function by acting as a cofactor (something that enables function) for numerous enzymes involved in energy metabolism, nerve, heart and vascular function and muscle contraction/relaxation.

We don’t need supplements to maintain adequate magnesium levels if we eat a diet rich in green leafy vegetables, whole grains, nuts, avocado, legumes and seeds.  Certain medications contribute to deficiency by increasing loss in urine.  The most common medications that do this are diuretics, amlodipine, tacrolimus, and proton-pump inhibitors like Prilosec, Nexium and Aciphex.  Magnesium deficiency may cause muscle cramps, metabolic syndrome/diabetes, osteoporosis, worse migraine headaches, high blood pressure, heart attack and cardiac arrhythmias. 

Supplement makers currently promote magnesium to treat stressed mood and fatigue, which could expand their market to just about everyone.  Supplements for those symptoms would only be effective if low magnesium levels were the cause of the problem.  In other words, if your tank (of magnesium) is already full, topping off with a supplement won’t magnify your energy and mood, though supplemental magnesium might improve mood if it alleviates distressing constipation.

Magnesium oxide is the least expensive magnesium salt (a salt is a substance combining a positively and a negatively charged substance) and is poorly absorbed from our digestive tract.  Because much of it passes through to the colon, it pulls water with it, loosening stool and alleviating constipation.  Any other salt of magnesium in high doses can similarly overwhelm the gut’s ability to absorb it, resulting in looser stool, also. We absorb a greater percentage of lower doses of ‘organic’ salts like magnesium citrate, malate, threonate or biglycinate.  Once the magnesium part of it is absorbed, they all function the same in the body, notwithstanding the hype that is used to promote particular supplement brands.  The minimum daily requirement of magnesium from all sources is about 30-80 mg for children, 400mg for adult males and 320mg for adult females, not typically obtainable from the plants-poor, animal product-rich diet of many in the U.S.