Exploratory study to evaluate two clinical methods for assessing moisturizing effect on skin barrier repair.

Background: Two clinical methods of assessing a moisturizer's effect on stratum corneum (SC) barrier repair were evaluated in female subjects with dry skin, to identify an assessment method for future studies.
Methods: In this single-centre, split-body study, women with dry skin applied moisturizer before (method A) or after (method B) SC barrier perturbation using D-Squame® stripping discs. Transepidermal water loss (TEWL) and residual protein on D-Squame discs were assessed over 14 days.
Results: Twenty-four subjects were included. For method A, the mean slope values of plots of 1/TEWL vs cumulative protein removed decreased over time for both treated and untreated areas, indicating improved SC barrier quality. There were no significant differences between treated and untreated areas, although a trend to a more negative slope was observed by Day 14 in the treated areas (P = 0.082), suggesting treatment improved barrier quality. For method B, using pre- and post-stripping as covariates, no statistical differences/trends were observed between treated and untreated areas for change in TEWL from post-stripping to any evaluation from Days 3-14. TEWL values returned towards pre-stripping values for treated and untreated areas by the initial Day 3 evaluation.
Conclusion: For method A, there were trends suggesting the moisturizing treatment improved SC barrier quality. For method B, there were no significant differences/trends between treated and untreated areas. Further assessment with different methodologies is warranted to design appropriate clinical protocols for evaluating accelerated skin barrier repair. These data are insufficient to conclude whether the product or methodology was responsible for the results.
(© 2019 The Authors. Skin Research and Technology Published by John Wiley & Sons Ltd.)