An ex vivo procedure to select compounds for their antioxidant behavior in a composition to be applied topically to the skin, in which the selection procedure comprises determining the ability of the compound to inhibit the formation of both lipid hydroperoxides in the skin induced by ultraviolet radiation and inhibit reactive oxygen species induced by ultraviolet radiation in the epidermis； wherein the determination of the inhibition of the formation of reactive oxygen species induced by ultraviolet radiation in the epidermis comprises obtaining images of the skin tissue using fluorescence intensity imaging of two photons； and wherein the determination of the inhibition of the formation of lipid hydroperoxide in the skin induced by UVR comprises the steps of applying a composition containing antioxidants and a placebo composition to produce a site in different areas of the skin of a subject of the antioxidant skin that contains antioxidant and skin lipids and a placebo skin site that contains placebo and skin lipids； apply a strip to the antioxidant skin site and the placebo skin site to produce a sample of the antioxidant strip containing antioxidant and skin lipids and a placebo strip sample containing placebo and skin lipids ； removing said strip samples from the skin and exposing said strip samples of the skin to UVR to form a UVR-induced antioxidant / lipid reaction product in the antioxidant strip sample and a placebo / lipid-induced reaction product UVR in the placebo strip sample； Contact the strip sample with antioxidant and the strip sample with placebo with solvent separately to prepare a first extract containing UVR-induced antioxidant / lipid reaction product and a second extract containing placebos / lipid reaction product UVR induced； analyze said first or second extracts for the lipid hydroperoxide content for each extract； and compare the lipid hydroperoxide content of the first extract with the lipid hydroperoxide content of the second extract.Un
