Magnesium oil (also referred to as transdermal magnesium, magnesium hexahydrate) is a compound of magnesium chloride dissolved in six molecules of water, with magnesium as the alkaline earth metal and chlorine as the nonmetal, it is a concentrated magnesium chloride solution. In reality, it is not a oil, as it is not composed of one or more hydrocarbons. Magnesium oil is supposed to be applied to the skin as an alternative to taking a magnesium supplement by mouth, although it is ineffective and scientifically unsupported due to lack of any convincing data that magnesium is absorbed in significant amounts through the skin.