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Comparative Effects of Retinoic Acid, Glycolic Acid and a Lipophilic Derivative of Salicylic Acid on Photodamaged Epidermis

Background: Studies comparing purported antiaging compounds are rare. Objective: To compare in a randomized, placebo-controlled double-blind study 10% glycolic acid (GA), 2% 2-hydroxy-5-octanoyl benzoic acid (β-lipohydroxy acid, LSA) and 0.05% all-trans-retinoic acid (RA). Methods: Women volunteers treated one forearm twice daily with one of the active products and the other one with the vehicle. Comparative evaluations of efficacy were made using histochemistry and quantitative immunohistochemistry. Results: Improvement in the various epidermal compartments was the most prominent finding at the RA-treated site. The LSA-treated site also exhibited similar positive changes, although to a lesser degree. GA showed no significant effect. Conclusion: In the presently tested concentrations and formulations, RA had a beneficial impact upon the aging epidermis. LSA mimicked RA but with somewhat lesser efficacy. By contrast, GA appeared almost inactive.