The oxide form of magnesium is not only the poorest-absorbed form, it’s also the chief culprit for causing a laxative effect. Essential Mg does not contain magnesium oxide. Magnesium citrate is an excellent form of magnesium, but in high amounts it too can cause a laxative effect. Essential Mg contains magnesium citrate, but in amounts that come nowhere near creating that issue. The main type of magnesium in Essential Mg is magnesium bisglycinate (aka glycinate), which is not only a highly bioavailable form, it has the least potential for creating a laxative effect. This is also true with the succinate, malate and taurinate forms found in Essential Mg.