Clinical and histological effects of glycolic acid at different concentrations and pH levels

BACKGROUND. Much has been said about the effects of glycolic acid with little scientific evidence to substantiate the findings. OBJECTIVE. This study reports on the clinical and histological effects of glycolic acid at pH levels 3.25, 3.80, and 4.40, and at 3.25%, 6.50%, 9.75%, and 13.00% on ichthyotic/xerotic skin. METHODS. Product treatment consisted of a 2-week washout period followed by 3 weeks of product application (BID) with a 1-week regression period. Shave biopsies and clinical evaluations for dryness, moisturization, and transepidermal water loss were made at baseline, 1, 2, and 3 weeks of use, and at the regression period. RESULTS. Clinically, ichthyotic/xerotic skin was normalized with histologic evidence of stratum corneum thinning, viable epidermal thickening, and marked increases in glycosaminoglycan and collagen content. CONCLUSION. All pH levels and concentrations demonstrated significant improvement in the condition of the skin with trends implying that increasing the pH increases efficacy.