A topical sunscreen composition includes metal oxide sunscreen particles, polylactic acid, and a cosmetic carrier in which the metal oxide sunscreen particles and polylactic acid are dispersed. A method of preparing a topical sunscreen composition includes dispersing metal oxide sunscreen particles and polylactic acid in a cosmetic carrier. A method of protecting human skin from ultraviolet (UV) radiation includes applying to human skin a topical sunscreen composition including metal oxide sunscreen particles and polylactic acid dispersed in a cosmetic carrier.