A novel enzymatic assay for the quantification of skin surface lipids.

The applicability of a novel enzymatic assay for quantifying skin surface lipids was investigated experimentally. The standard curves for the assays of glycerol esters, free fatty acids, and cholesterol and its esters were linear over a wide range of lipid concentrations, which ensures the accuracy of measurements. The assay system also showed good simultaneous reproducibility. There were significant positive correlations (P < 0.001) between the quantities of glycerol esters, free fatty acids, and cholesterol and its esters sampled from the skin surface of women when measured by the enzymatic assay compared with the gas chromatographic method. The enzymatic assay was applied to studies of the relationships between age, acne and menstrual cycle, and skin surface lipids in women. The quantities of glycerol esters and free fatty acids reached peaks in females in their twenties and thirties. Increased quantities of glycerol esters, free fatty acids, and cholesterol and its esters were observed in women with acne compared with women without acne. Among the women with acne, those in the premenstrual phase of the menstrual cycle showed increased levels of glycerol esters, free fatty acids, and cholesterol and its esters compared with those in the menstrual phase. The results suggest that the enzymatic method is a satisfactory new technique for the quantification of skin surface lipids.