Bioven Ingredients Light magnesium oxide is white amorphous powder, odorless, tasteless, and non-toxic. Melting point is 2852 ℃. Light magnesium oxide is insoluble in water and ethanol, soluble in acid and ammonium salt.Magnesium is a naturally occurring mineral. Magnesium is important for many systems in the body especially the muscles and nerves.Magnesium oxide is used as a supplement to maintain adequate magnesium in the body. Magnesium oxide is also used as an antacid to treat indigestion, or as a laxative to relieve occasional constipation.