5 Things That Cosmetics Can Do
While there are hundreds of types of cosmetics and thousands of cosmetic brands, there are really only 5 things that cosmetics do. If you want to be a well-rounded cosmetic formulator you should be familiar with how to make at least one formula in each category. 
Cleaning
Getting rid of dirt and oil from the surface of skin and hair is the purpose of a large segment of cosmetic products. This includes products like shampoos, body washes, cleansing bars, facial cleansers and more. The key raw material responsible for making most of these products work are surfactants. If you want to get good at formulating cleansing products, you’ve got to learn surfactant science.
Conditioning
Where cleaning cosmetics leave off, conditioning cosmetics begin. Removing dirt solves some problems but even in their natural states hair and skin may not look or feel the way people want. For this reason conditioning or moisturizing products are needed. These include products like conditioners, skin lotions & creams, moisturizers, gels and more. There are a wide range of ingredients that can condition such as occlusives, humectants, emollients, surfactants, and polymers. And they work in slightly different ways. To get good at creating conditioners you have to not only know these ingredients but you also need to know what properties make a surface feel conditioned or moisturized.
Coloring
Since cosmetics are used to enhance or change the appearance of skin, hair and nails one of the most obvious ways to do that is by changing the color. Cosmetics that change the color include hair coloring, sunless tanners, lipstick, blush, eyeshadow, nail polish, and pretty much any other color cosmetic. The ingredients that make most of these products work are highly regulated in the cosmetic industry and include dyes and pigments made from minerals, synthetic organic molecules, or other natural colorants. For hair colors bleach is used to make the color lighter while polymeric dyes are used for other colors. Color cosmetics are a specialized area of formulating and require special equipment to make more sophisticated formulations. If you were looking to start your own line, making color cosmetics is one of the most difficult places to start.
Change the shape
Another way that cosmetics can change the appearance is by changing the shape of the surface on which they are applied. This function is mostly limited to hair products like styling products, relaxers, and perms. There isn’t a lot you can do to change the shape of skin using cosmetics although some might argue skin tightening products do that. In any event, the key raw materials that help cosmetics change the shape of the surfaces include polymers, resins, oils, and waxes.
Change the odor
Although looking good is an important function of cosmetics, making people smell good is another thing that cosmetics can do. Cleaning products will remove odors but cosmetics like deodorants, perfumes, and fragranced cosmetics can change the way a person smells. The main ingredients that have this effect include things like synthetic odor molecules, resins, extracts, and oils. To be able to formulate a good fragrance requires years of specialized training. There are literally thousands of ingredients with different odors that you have to learn and discover how they interact to create a pleasing odor. Those fragrances then have to be formulated into finished products that work for consumers. Perfumers are like the fashion designers of the cosmetic industry.
That about covers it. All the hundreds of thousands of beauty products only do one or more of these five things. There are a number of products that seem like cosmetics like sunscreens, antiperspirants or anti-dandruff products but these are actually over the counter drugs (at least in the US) and they wouldn’t technically be considered cosmetics.
