A review. It has long been known that UV light can interact directly with biol. chromaphores such as deoxyribonucleaic acid (DNA) and in so doing, can damage those mols. More recently the role of UV-light in the generation of free radicals in the skin has suggested a 2ndary indirect route for biol. damage. Here, the authors describe a series of in vitro, ex vivo and in vivo experiments designed to investigate whether certain antioxidant materials are able to prevent free radical initiated damage to biol. mols. during exposure to UV-light. A number of antioxidant materials are shown to be effective at preventing DNA damage (measured by alk. comet assay) in a tissue culture model and at preventing lipid peroxidation in both an in vitro model and an ex vivo human stratum corneum tape stripping model. The performance of these materials when used in combination can show a synergistic or optimized effect. However when antioxidant materials proven to be effective at preventing DNA damage and lipid peroxidation are incorporated into a sunscreen product, no effect is measurable on the sun protection factor (SPF) of the product.