Lipophilic penetration enhancers and their impact to the bilayer structure of stratum corneum lipid model membranes: Neutron diffraction studies based on the example Oleic Acid

► We study the impact of oleic acid to the assembly of stratum corneum model membranes. ► Deuterium-labeling is used to localize oleic acid inside the membrane. ► The presence of oleic acid is associated with a significant loss of lamellar order. ► Perturbation of lipid assembly is crucial for penetration enhancer activity of oleic acid.