Background: Sensitive skin exhibits impaired skin barrier function. The lipid composition of the skin, a pivotal element within the stratum corneum’s “brick-and-mortar” structure, plays a dual role: it is integral to cell differentiation processes and serves as a vital nutrient reservoir for cutaneous microbiota, thereby influencing the skin’s microecological balance. There is a notable research gap concerning the comparative analysis of physiological parameters and lipid profiles among individuals with sensitive dry skin (SDS), sensitive oily skin (SOS), and healthy skin (HS). Methods: A total of 95 females (18–25 years) were grouped: SDS (n = 32), SOS (n = 31), and HS (n = 32). Stratum corneum water content, oil content, and TEWL were measured. Lipids from sebaceous glands and stratum corneum (tape-stripping) underwent UPLC-QTOF-MS analysis. Differential lipids were identified via OPLS-DA, volcano plots, and LMSD. Results: In terms of physiological indicators, notable disparities emerged in oil content and stratum corneum water content between the SOS and both the HS and the SDS. Sensitive skin, whether dry or oily, displayed a higher transepidermal water loss (TEWL) value than healthy skin, reflecting a declined state of skin barrier function. Regarding the sebum samples, the relative percentages of sphingolipids (SP) and glycerophospholipids (GP) were significantly higher in SDS. Regarding the stratum corneum samples, the percentages of SP in SDS were significantly higher. Conclusions: This study, for the first time, conducted a comprehensive analysis of the skin’s physiological properties, lipidomics of sebum, and stratum corneum lipids among groups with SDS, SOS, and HS. These observations indicate a profound association between skin barrier dysfunction in SDS individuals and, in particular, sphingolipids (SP).

The abnormal barrier function of the stratum corneum is a significant characteristic of surface-active agent-induced inflammatory skin diseases, and its cause is closely related to the abnormal lipid components of the stratum corneum. Total saponins of Panax notoginseng (TSPN) have significant potential in improving inflammatory skin barrier function. This study aims to investigate the barrier repair efficacy of TSPN using the EpiKutis^® skin model and to explore the potential mechanisms through multi-omics analysis based on transcriptomics, proteomics, and lipid metabolomics. We found that TSPN could ameliorate Sodium dodecyl sulfate (SDS)-induced barrier impairment in the EpiKutis^® model, alleviating stratum corneum thickening and upregulating the expression of barrier-related proteins, e.g., Filaggrin, Involucrin, and Loricrin. Through an integrated multi-omics network, we identified seven key target proteins and screened six lipid metabolites, which are involved in lipid metabolism and exert barrier-repairing effects through five pathways. The result indicated that TSPN might repair the epidermal barrier by regulating the phosphatidylinositol 3 kinase (PI3K)-protein kinase B (AKT)-mediated proliferation pathway, Mitogen-activated protein kinase (MAPK)-mediated apoptotic pathways, sphingolipid synthesis, Calcium/calmodulin-dependent protein kinase II beta (CAMK2B)-mediated actin cytoskeleton regulation, and Inositol-trisphosphate 3-kinase B (ITPKB)-mediated phosphatidylinositol signaling system. Further study is needed to explore the mechanism of the molecular link between lipid abnormalities and skin barrier function.