Magnesium oxide is a type of magnesium that also contains oxygen. Other forms of magnesium supplements include: Magnesium chloride Magnesium citrate magnesium glycinate Magnesium lactate Magnesium malate Magnesium orotate Magnesium sulfate Magnesium L-threonate Of the different types, magnesium citrate is among the most easily absorbed in the body and one of the most popular forms found on drugstore shelves.