It is really a simple matter for a cosmetic chemist to start from an existing formula and recreate something that works just as well. Substituting out one ingredient for another is not hard.
Mascara is a cosmetic commonly used to enhance the eyelashes.
It may darken, thicken, lengthen, and/or define the eyelashes.
Getting a formulation patent is a gratifying experience for a cosmetic chemist.
You get to see your name listed in the official rolls of the US patent office and you get to add it to your resume or CV. It’s especially great if the company you are working for pays all the required legal fees.
One of the main reasons people think to get a patent is so they can prevent their competition from copying their formulas.