Question: what is the difference between magnesium oxide and magnesium hydroxide?
Answer: “Magnesium Oxide is less bioavailable and when bound with water to make magnesium hydroxide, it is generally used to alleviate heartburn and constipation—for example, Milk of Magnesia,” Dowd says. She explains that Milk of Magnesia provides 500 mg of magnesium hydroxide (magnesium oxide, plus water) per tablespoon.