A surfactant is a substance that dissolves in water to allow a product to remove dirt from surfaces like the skin. They are are particularly effective in the removal of oily, potein-based and carbohydrate-based impurities as they emulsify and suspend such particles and stop them ‘sticking’ to the skin again before being washed away. Surfactants allow impurities not able to be dispersed with water alone to be cleansed with the addition of water.
Each surfactant molecule has a head that is attracted to water and a tail that repels water while attaching itself to oils and greasy dirt. Thus latched to both water and the dirt, a surfactant allows the latter to be swept away along with the water.
