Comparative analysis of skin surface lipids of the labia majora, inner thigh, and forearm.

The purpose of this study was to develop a procedure for the collection of skin surface corneocyte lipids from the semioccluded and intimate regions of the labia majora and inner thigh of women, to evaluate the polar and nonpolar composition, and to compare the distribution of the lipid classes relative to a collection of lipids from the forearm. The solvent system of ethanol-cyclohexane was well tolerated across all sites. While the yield of polar lipids was similar across all 3 sites, there were only marginal differences in the relative abundance of ceramides, a class of lipids closely associated with skin barrier activity. The yield of neutral lipids was significantly less for the labia majora and was associated with a reduced yield of wax esters, triglycerides and free fatty acids, likely associated with reduced sebaceous gland activity. Factors that may contribute to an inferior skin barrier activity for the labia majora are discussed and suggest a possible deficiency of ω-6 fatty acid linked to the sphingosine base of ceramide EOS.