Horse oil has the most similar structure to human skin than other oils therefore it has strong penetration force to the skin. It penetrate skin fast, give skin hydration and necessary nutrition. Mongolian horse is pasture fed with natural grass, living freely in the steppe, therefore the unsaturated fatty acid content is relatively high to other horses around the world and therefore make a superior oil for this soap product. Unsaponified horse oil left on the soap surface will form a thin oil film on the skin, preventing secondary oxidation and inhibit various skin problems.