Figure 2: Analysis of skin surface lipid (SSL) fractions of human samples (pooled extracts of 30 healthy individuals) and of non-human primates (from 1 to 5 pooled individuals in each sample) performed by Thin Layer Chromatography (TLC) with double-solvent system resolution. The effective chemical characterization of each lipid fraction was checked by Gas Chromatography—Mass Spectrometry (GC-MS) analysis (for quantitative results see Table 1).