关键词: 弹性, 紧致度, 双光子成像技术, 超声, 化妆品功效评价, 弹性纤维, 胶原纤维

Abstract:

By evaluating the efficacy of a cosmetics with palmitoyl pentapeptide-4 as the main functional ingredient, the study establishes a clinical evaluation method system for firming efficacy. Thirty-one female subjects aged 20-50 were screened, and the skin indexes including the objective test data, image methods and subject self-assessment methods were evaluated after using the product for 0 week, 4 weeks and 8 weeks, respectively. The parameters of skin elasticity and skin dermal density in the cheeks and canthus of the subjects, as well as the TPEF images and the SHG images, were captured, and comparative analyses were carried out. The results show significant changes in skin elasticity, dermal density （P<0.001） and DEJI （P<0.01） after 8 weeks, which are consistent with the results of the subjects’ self-ratings, indicating a correlation between the methods. This research can provide technical supports for the establishment of a cosmetic firming efficacy evaluation method system.

Key words: elasticity, firmness, two-photon imaging technology, ultrasound, evaluation of cosmetic efficacy, elastin fibres, collagen fibres