A Double-Blind, Comparative Clinical Study of Newly Formulated Retinol Serums vs Tretinoin Cream in Escalating Doses: A Method for Rapid Retinization With Minimized Irritation

Objective: The goal of this 12-week, double-blinded, controlled, clinical study was to compare the efficacy, tolerability, and consumer acceptance of three novel retinol serums to tretinoin. Method: Forty-five photoaged females ages 35-65, Fitzpatrick skin types I-IV, with moderate wrinkling were enrolled in the 12-week study. A step-up protocol for increasing the dose of retinol serum (0.25%, 0.5%, 1.0%) or tretinoin cream (0.025%, 0.05%, and 0.1%) in combination with a test moisturizer or currently marketed dermatologist-recommended moisturizing cream was used. Overall severity of investigator graded photodamage, subject assessed photodamage, and tolerability criteria were evaluated using a 5-point ordinal scale at weeks 4, 8, and 12. Facial photography occurred at each visit and TEWL was measured at baseline and week 12. Histologic evaluation of punch biopsies was completed on baseline and week 12 samples. Results: After 12 weeks of use, both retinol serum and tretinoin demonstrated parity across investigator and subject assessment measurements as well as diagnostic measures including TEWL. Retinol serum subjects showed significant week 4 improvement in visual skin smoothness compared to tretinoin subjects (P=0.031). There was highly significant improvement in skin dryness with the retinol serum (P<0.001) not seen in the tretinoin group. Histologic analysis of baseline and 12-week punch biopsies demonstrated newly formed collagen and greater epidermal thickening in retinol serum subjects compared to tretinoin treated subjects. Conclusion: Retinol serum (0.25%, 0.5%, 1.0%) was safe and effective with equivalent/or better performance and tolerability than tretinoin creams.