27887 Skin exfoliation with low concentrations of alpha hydroxy acids and poly hydroxy acids when incorporated into wash-off or leave-on products using a novel abbreviated model to measure cell turnover rate

Abstract

Alpha hydroxyacids (AHAs) and polyhydroxy acids (PHAs) are known for enhancing skin cell turnover rate. Typically, 8-10% concentrations have been evaluated for their exfoliation potential. Glycolic acid and gluconolactone at 2% in a cleanser and leave-on cream along with a 1% lactobionic acid cream were assessed for cell turnover rate. A novel, abbreviated clinical method to assess skin cell turnover rate using fluorescence staining of the stratum corneum was conducted. Dansyl chloride 5% was applied to volar forearms under occlusion for an abbreviated time of 6 hours. Digital photographs were taken under ultraviolet light over 7 days; images were analyzed to determine fluorescent intensity. Products in standardized vehicles were applied twice daily. Additionally, a 2% gluconolactone body lotion was evaluated for consumer perception of benefit after 2 weeks of daily use. Cell turnover rate was significantly increased for all formulations at these lower concentrations (P ˂ .05). The 2% glycolic acid cleanser (n = 34) and cream (n = 31), the 2% gluconolactone cleanser (n = 34) and cream (n = 32) and the 1% lactobionic acid cream (n = 32) all demonstrated an increase in exfoliation (time to 50% reduction of dye) compared with untreated (P ˂ .05). Consumers noted corresponding skin cell turnover benefits of the 2% gluconolactone body lotion (n = 34) including: skin is lightly exfoliated (94%); skin feels renewed (100%); dry, dull skin is revitalized (97%); and skin texture is smoother (100%). AHAs and PHAs are well-known exfoliators. In cleanser or cream form and at concentrations of 1-2%, meaningful increases in cell turnover rate were noted with consumer perceivable exfoliation benefits.