This International Standard specifes an in vivo method for assessment of the UVA protection factor (UVAPF) of topical sunscreen products. This International Standard is applicable to cosmetics, drugs and other products intended to be topically applied to human skin, including any component able to absorb, refect or scatter UV rays.It provides a basis for the evaluation of sunscreen products for the protection of human skin against UVA radiation from solar or other light sources.