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. Objec tive: To compare in a randomized, placebo-controlled double-blind study 10% glycolic acid (GA), 2% 2-hydroxy-5-octanoyl benzoic acid (beta-lipohydroxy acid, LSA) and 0.05% all-trans-retinoic acid (RA). Methods: Women voluntee rs treated one forearm twice daily with one of the active products and the other one with the vehicle. Comparative evaluations of efficacy were made u sing histochemistry and quantitative immunohistochemistry. Results: Improve ment in the various epidermal compartments was the most prominent finding a t the RA-treated site. The LSA-treated site also exhibited similar positive changes, although to a lesser degree. GA showed no significant effect. Con clusion: In the presently tested concentrations and formulations, RA had a beneficial impact upon the aging epidermis. LSA mimicked RA but with somewh at lesser efficacy. By contrast, GA appeared almost inactive.