Magnesium: which type?
Magnesium is sold as 6 different salts, each in more than one format. They are not interchangeable: each carries a different amount of actual magnesium per gram, and they differ in how well they are absorbed and tolerated. So each type is compared on its own, and every price below is per 200 mg of elemental magnesium — not per capsule and not per bottle.
The choice of type matters more than the choice of brand within it: the cheapest type here is 222× cheaper per dose than the dearest.
The densest and cheapest source of elemental magnesium per capsule, and the least absorbable. Price per dose flatters it; that is the point of showing it.
Compared on elemental magnesium. Labels commonly print the malate compound weight, which is several times the magnesium it carries.
Labels here are unusually misleading: compound weight is often printed instead of elemental magnesium. Several products sold as glycinate are blended with oxide.
Widely sold and cheap per elemental milligram. Compared on elemental magnesium, not on the weight of the citrate compound.
Only the powder states elemental magnesium on its panel. The capsules from the same brand give the compound weight alone, so they cannot be priced per dose.
The most expensive form per elemental milligram by a wide margin. Sold almost entirely as branded Magtein.
Cheapest means the cheapest we track, not the cheapest that exists, and a low cost per dose is a statement about price rather than about how well a form is absorbed — which we do not measure. How these numbers are made: How we compare.
- Servings per container are derived from net weight rather than read off the label, except where a note on the product says otherwise.
- Most source records have not been checked by a person. The ones that have say so.
- Amazon and Walmart are not included, so “cheapest” means cheapest among the retailers we track.
- Prices go stale. Each one shows when it was last checked, and says so when it is older than the retailer allows us to cache it.