What does broad spectrum sunscreen mean? You see it often on sunscreen labels, but what exactly does it mean? Broad spectrum sunscreen refers to sunscreen that protects you from both UVA rays and UVB rays. UVA rays are responsible for numerous aging-related skin issues, such as skin discoloration, skin thinning, and loss of collagen in the skin. UVB rays are responsible for the heat and burning sensation of a sunburn. Both can be avoided by wearing a broad-spectrum sunscreen.