Emulsifiers are used in creams and lotions to mix water with oils. Since water and oil do not mix but stay separated, emulsifier acts like an additional agent to form a homogenous mixture keeping water and oil together. Emulsifiers blend and hold together the ingredients that would not usually mix very well. In cleansing products, the ability of an emulsifier to combine waters and oils gives a final product the ability to both cleanse and condition the skin at the same time.
There are 2 types of emulsifiers.
Oil-in-water (O/W) emulsifiers keep oil drops packed in water. O/W emulsifiers are high water content and, therefore, low in cost. These emulsions are favored for their stability and flexibility, as well as their non-greasy, non-oily feel. They are used more in moisturizing products, e.g. body lotions, day creams.
Water-in-oil (W/O) emulsifiers keep water drops packed in oil. W/O emulsifiers are used for a fatty feel, offer longer moisturising effect, wash-off resistance, and barrier protection. They spread more easily on the skin, and often leave a lubricious, rich or oily feel, favored by mature clients and consumers with dry skin. These formulas tend to be less cost-effective, as oils are always more costly than water and these types of emulsions are generally more difficult to produce, e.g. night & sun protection creams.
They are derived from natural oils such as coconut, palm kernel, sunflower, wheat germ, and so on.