Why the form of magnesium matters more than the milligrams
Two bottles can both say 400 mg and deliver very different amounts to your cells. The difference is in the small print after the word magnesium.
Magnesium is involved in several hundred reactions in the body, from the production of cellular energy to the relaxation of muscle and the regulation of the nervous system. It is also one of the nutrients that modern diets most often fall short on, which is why it is among the most purchased supplements in the world. Most of what is purchased, though, is the wrong form.
Magnesium never travels alone
Magnesium cannot be put in a capsule by itself. It has to be bound to something, and the molecule it is bound to decides how much of it the body absorbs and what else it does along the way. That partner molecule is the form, and it is written on the label right after the word magnesium: oxide, citrate, glycinate, malate, threonate, and others.
Oxide: the most common and the least useful
Magnesium oxide is inexpensive and dense, so a small tablet can carry a large number on the label. Very little of it is absorbed. Most of it stays in the gut, where it draws in water and loosens the bowel, which is why it is the active ingredient in several laxatives. A 400 mg tablet of oxide and a 400 mg capsule of glycinate are not the same thing in any way that matters to your cells.
Citrate: absorbed well, with a side effect
Magnesium citrate is absorbed reasonably well and is the right choice when a gentle effect on the bowel is wanted. For people who do not want that effect, or who are taking magnesium for sleep, muscle tension, or stress, it is not the best fit.
Glycinate: absorbed well, and calming on its own
Magnesium glycinate binds the mineral to glycine, an amino acid that the body uses as a calming neurotransmitter. The chelate crosses the gut wall efficiently, does not loosen the bowel at ordinary doses, and the glycine it carries supports relaxation in its own right. For sleep, muscle relaxation, and stress support, it is the form a physician reaches for first.
Reading the label
Look for the form named after the word magnesium, and look for the phrase fully reacted or chelate, which means the mineral is bound to glycine rather than mixed with it. Then check the serving size: some products reach their headline number only at four or six capsules. The number that matters is the amount of elemental magnesium per serving, in the form the body can use.
Fully reacted bisglycinate chelate in a vegetable capsule with nothing else. Our own formula, made in an NSF GMP registered facility.