SHE 203

Types of emulsifiers in cosmetics are divided into two categories: water in oil W/O and oil in water O/W. In water-in-oil emulsions, the oil surrounds the water and touches the skin first. The amount of fat depends on its formula. In oil-in-water emulsions, the water surrounds the oil. This method creates creams and lotions that feel moist and less greasy. There is very little oily residue when absorbed into the skin

Emulsifiers in cosmetics stabilize the emulsion by increasing its kinetic stability. Emulsifiers are soluble in both oil and water and do this by absorbing one end of the molecule into water (hydrophilic) and absorbing the other end into fats/oils (lipophilic).

A variety of cosmetic emulsifiers and choosing the right one means finding a molecule with roughly equal absorption of water and oil in your particular formula. This means finding an emulsifier with any of the following:

Positively charged (cationic) – best used with slightly acidic or neutral mixtures

Negative charge (anionic) - best used with alkaline mixtures

Uncharged (non-ionic) – usually used alone or with a charged emulsifier to increase stability