Types of Magnesium Explained
Magnesium is sold as glycinate, citrate, oxide, malate, threonate, chloride and taurate, plus blends. The compound determines how much elemental magnesium a given milligram figure represents, and oxide carries the most per gram while chelated forms such as glycinate carry less.
Magnesium supplements are sold as compounds, not as magnesium on its own. The mineral is always bound to something — an amino acid, an organic acid, or a simple salt — and that partner determines the name on the bottle, how much elemental magnesium the compound carries, and how the product behaves.
Why the compound changes the number
Elemental magnesium is the magnesium itself, as distinct from the weight of the whole compound. Magnesium oxide is a small molecule, so a large proportion of its weight is magnesium. Magnesium glycinate binds magnesium to two glycine molecules, which are comparatively heavy, so a smaller proportion of the total weight is the mineral.
This is why “500 mg magnesium oxide” and “500 mg magnesium glycinate” do not describe the same amount of magnesium. Good labels state both figures. Where only one appears, check whether it is described as elemental — and treat the front-of-bottle number with suspicion until you have.
The compounds you will see
Glycinate and bisglycinate
Magnesium bound to the amino acid glycine. Bisglycinate means two glycine molecules; in practice the two names are used interchangeably on labels. Widely sold, usually at moderate elemental doses that require two or three capsules per serving.
Citrate
Bound to citric acid. Common in both capsules and powders, and the form most often used in products intended to be dissolved in water. Also sold at pharmacy strength for a specific bowel-preparation purpose, which is a different product from a daily supplement despite the shared name — check the dose.
Oxide
The simplest and cheapest compound, carrying a high proportion of elemental magnesium by weight. Frequently used in multivitamins and low-cost single-ingredient tablets, where it lets a label show a large milligram figure inexpensively.
Malate, taurate, threonate, chloride
Bound respectively to malic acid, taurine, threonic acid and chloride. These are marketed with distinct positioning; from a label-reading perspective the questions are the same — what is the elemental dose, how many units make a serving, and what does that cost per day.
Blends
Products combining three or more forms are common. The panel should break out how much of each is present; where it does not, you cannot know the split.
Which to compare against which
The practical choice for most people is between the two most-sold forms — see magnesium glycinate vs citrate — or between a chelated form and the inexpensive salt, covered in magnesium oxide vs citrate. For what the number on the panel actually represents, see reading elemental magnesium on a label.
Once you know which form you want, our magnesium comparison filters the catalogue by type, strength and brand.