Thickeners and emulsifiers determine the texture, flow and stability of a formula. In creams and lotions, emulsifiers keep the oil and water phases together without separating; in gels, shampoos and liquid products, the desired viscosity is achieved with thickeners such as Xanthan Gum, Carbomer and Hydroxyethylcellulose.
Fatty alcohols, esters and fatty acids such as Cetearyl Alcohol, Glyceryl Stearate and Stearic Acid contribute to both body and emulsion stability. Cera Alba, Candelilla Wax and Carnauba Wax provide structure in lipsticks, balms and stick products.
The right thickener is chosen according to the pH, electrolyte content and processing temperature of the formula. Some polymers, such as carbomer, only thicken once neutralized, so the choice should be made with the whole formula in mind.