Magnesium sulfate is a common mineral pharmaceutical preparation of magnesium, commonly known as Epsom salt, used both externally and internally. Magnesium sulfate is highly water-soluble and solubility is inhibited with lipids typically used in lotions. Lotions often employ the use of emulsions or suspensions to include both oil and water-soluble ingredients. Hence, magnesium sulfate in a lotion may not be as freely available to migrate to the skin nor to be absorbed through the skin, hence both studies may properly suggest absorption or lack thereof as a function of the carrier (in a water solution vs. in an oil emulsion or suspension). Temperature and concentration gradients may also be contributing factors to absorption.