Most people who work in the cosmetic industry for large to medium sized companies specialize in one type of cosmetic product. They are limited to hair products or skin products and rarely is there an overlap. Formulators at contract manufacturer or consultants have much more opportunity to work on the different types of cosmetic products, but even they are limited by the projects that come to them. If you want to be a complete cosmetic chemist and maximize your career flexibility, you should learn about the products in all cosmetic categories and the basics of how to create those formulas. The first step to that is to know the products in each of the categories.