Exposure of human skin to ultraviolet (UV) radiation from the sun not only induces the production of enzymes (matrix metalloproteinases) that degrade collagen, but also inhibits the synthesis of new collagen by inhibiting the synthesis of procollagen. This UV-induced inhibition of the synthesis of collagen can be prevented by the topical application of a retinoid or c-JUN inhibitor to the skin prior to exposure to UV radiation.