A Highly Efficient and User-Friendly Sensitive Skin Model on the Forearm.

Background: Sensitive skin is a worldwide skin problem, and its assessment of therapeutic efficacy traditionally relies on the facial stinging test. However, this test possesses certain limitations due to its restrictive application site, intense pain sensation, and adverse effects on physical appearance.

Objective: This study aimed to develop and evaluate a highly efficient and user-friendly sensitive skin simulation model, which combines tape stripping and capsaicin testing on the forearm (FA-TS-CAT), as an alternative to the facial stinging test.

Methods: A randomized, double-blind, placebo-controlled clinical trial was conducted involving 74 subjects. Skin redness (a* value), transepidermal water loss (TEWL), and self-assessment questionnaires were collected at different time points for analysis.

Results: Tape stripping 5 times and 10 min application of capsaicin test were identified as the optimal conditions for the FA-TS-CAT model. Consistent stimulation and natural recovery trends of a* value and TEWL were observed on both the FA-TS-CAT and facial capsaicin test (F-CAT) models within 50 min. After the 4-t-butylcyclohexanol complex emulsion was applied, the a* value in the FA-TS-CAT model exhibited a soothing trend similar to the F-CAT model, with a significantly reduced by 3.99-fold and 3.28-fold at T3 and T4 (p < 0.001), compared to the placebo. Notably, the test efficiency of the FA-TS-CAT model was threefold higher than that of the F-CAT model, and subjects showed more willingness to participate in the FA-TS-CAT test (95.95% vs. 4.05%).

Conclusions: These results indicated the FA-TS-CAT is a highly efficient and user-friendly model for sensitive skin, providing a reliable and valid method for clinical research in sensitive skin treatment.