Supplementary Material for: Lipidomics reveals the effects of detergents on skin surface lipids in young adults

Background: Detergent is a chemical product commonly used in people's daily life. Contact with detergent solutions can damage the human skin barrier and cause skin diseases. Skin surface lipids (SSLs) play a decisive role in skin barrier function. This study aimed to observe the changes of SSLs in young adults after exposure to detergent solutions to explore the underlying mechanism of skin barrier function damage.
Methods: A self-controlled study on youth adults was conducted in Zhengzhou, China, in November 2020. The study lasted for a total of 1 week, and skin barrier function was assessed by trans epidermal water loss (TEWL) values. The changes of SSLs before and after exposure to the detergent with subjects were measured using ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-QTOF-MS).
Results: The skin barrier function of subjects' hands was impaired after exposure to detergent (TEWL value increased, p< 0.001). A total of 520 SSLs were detected, divided into 6 main categories. The average relative abundance of these 6 major lipids decreased after exposure. Sphingolipids (mainly ceramides), free fatty acids (mainly long-chain fatty acids), cholesterol lipids, and glycerophospholipids are the most severely damaged lipids.
Conclusion: Detergent solutions can damage the skin barrier function and SSLs of young hands, interventions targeting SSLs to eliminate detergent damage to human skin may be of value.