JOURNAL OF COSMETIC SCIENCE 64 increased skin hydration (44.1% for the SSL mimetic and 48.8% for petrolatum) and decreased TEWL (-8.2% for the SSL mimetic and -7.1% for petrolatum). This demon- strates the difference between short- and long-term hydration and barrier function effects between the SSL mimetic and an occlusive ingredient such as petrolatum. Figure 2. Evaluation of short-term skin hydration 4 h posttest article application. Figure 1. Evaluation of barrier recovery (i.e., reduction in TEWL as compared to the same test site after acetone treatment but prior to test article treatment) 60 min posttest article application.

BOTANICALLY DERIVED SKIN SURFACE LIPID MIMETIC 65 In the fi nal study, the SSL mimetic produced statistically signifi cant ( p 0.001) higher percent changes in skin hydration, elasticity, and fi rmness than the vehicle (Figure 4). DISCUSSION The present research indicated that, overall, the SSL composition is consistent in a con- trolled population of 22-year-old females. Furthermore, there were strong correlations between the various SSL components, with the exception of squalene and cholesteryl es- ters. The concentration of FFA demonstrated the greatest variance between subjects and within multiple samples taken from the same subject. The variation in FFA may be due to the differences in the microfl ora of the subjects (16). When FFAs were combined with glycerides, the coeffi cient of variation decreased greatly between subjects and between samples taken from the same subject. The variation of this study’s results compared to previously published work could indicate that the collection methods, geographic location (10), gender, and age specifi city contribute to the distribution or collection of different lipid components on the skin surface. Additionally, factors such as race, hormone- containing birth control, and oily skin did not appear to affect SSL composition (unpub- lished data collected by Floratech). However, these factors could affect whether or not individuals are prone to acne or the total amount of SSLs on the skin. Figure 3. Evaluation of long-term skin hydration and skin barrier function after 2 weeks of test article use followed by 1 week of regression (no test article used).