The Fitzpatrick scale is a numerical classification system used to categorize human skin color and its response to ultraviolet (UV) radiation. Developed in 1975 by Thomas Fitzpatrick, a Harvard dermatologist, it's widely used in dermatology, cosmetics, and skincare to determine appropriate treatments and product recommendations. The Fitzpatrick scale helps dermatologists assess skin cancer risk, determine appropriate laser treatment settings, guide sunscreen recommendations, and customize skincare regimens. In clinical studies, it's an essential tool for ensuring diverse participant selection and analyzing how treatments perform across different skin types.