In the mid-1980s, Principal became interested in natural-beauty therapies, and in 1989, she created a self-named line of skincare products, Principal Secret. Over the past 25 years, Principal has built her skincare empire. In 2000, Principal became a member of the Society of Cosmetic Chemists (SCC). The SCC is dedicated to the advancement of cosmetic science, and strives to increase and disseminate scientific information through meetings and publications. In January 2011, she launched a line of jewelry called Keys & Hearts available on the same site as her skincare line.