The essential oil of Cymbopogon citratus (DC.) Stapf is widely used for the production of fragrances, cosmetics, and detergents. However, there is no information on the effects of formulations containing C. citratus essential oil (EOCC) on human skin. This study aimed to evaluate the effects of formulation containing EOCC on human skin physiology. The study involved participants of both sexes (n=12). Two areas (3 cm x 3 cm) were drawn on both forearms. One randomly chosen area was treated for 14 days, 2 times/day with polyacrylic acid gel containing 5% EOCC and the other was used as a control for the same time period. Transepidermal water loss (TEWL), hydration, epidermal lipids, and biomechanics were measured (D0 and D14). High resolution Sonography images were also obtained. Results revealed a significant decrease in TEWL, a significant increase in hydration, firmness and elasticity, and a decrease in lipids, in the areas treated with EOCC. Sonography showed an increase in echogenicity of the epidermis after applying the formulation indicating that the essential oil penetrates only the most superficial layers of the skin. Results also suggest that formulations containing EOCC are safe for topical application and can improve and protect human skin. Keywords: Cymbopogon citratus; essential oil; citral; lemongrass