Fatty acids

Fatty acids, like the fatty alcohols, are important raw materials for cosmetic ingredients such us surfactants, emulsifiers and emollients. Fatty acids are obtained by saponification of naturally-derived triglycerides. As such, they are seldom used in emulsions. They act as consistency regulators but tend to crystallize in the formulation.
Fatty acids especially stearic acids, are mainly used in the form of soaps. As the pH increases, they become truly anionic and act as oil-in-water (O/W) emulsifiers. forming a group of so-called stearate creams.
Commercially available stearic acids are often mixtures of C16 and C18 fatty acids, mainly I : 1. The preferred cosmetic quality with low odor is a triple-pressed stearine with an iodine value below 2. A special application of the fatty acids is their use in alcohol stick formulations, where stearic acid is dissolved in ethanol and then neutralized with sodium hydroxide. These hard sticks are used as deodorant bases.