Influence of hazelnut oil phospholipids on the skin moisturizing effect of a cosmetic emulsion

Synopsis Previous studies have shown significant differences between the moisturizing effects and skin tolerances of virgin and refined vegetable oils when incorporated in cosmetic emulsions. They have also shown significantly greater and longer lasting moisturizing potential for a cosmetic emulsion containing virgin vegetable oils when compared with refined oils in the same emulsion. Results were obtained with sweet almond and hazelnut oils. Hazelnut oil has now been analysed to show the effect of refining. The phospholipid content of the oil decreased from 286 ppm in virgin oil to traces in refined oil. These oils were added at 10% to a cosmetic emulsion applied twice a day for 28 days to the skin of 56 volunteers and the changes in moisturizing effect measured by means of the capacitance method (corneometer CM 240 Khazaka). Measurements were made under conditions of controlled temperature and humidity on the first day of application and repeated after 21 and 28 days of treatment. A significant increase in the moisturizing effect of the emulsion containing virgin hazelnut oil was found and this was itself significantly greater than the emulsion containing refined oil. Both emulsions had a greater moisturizing effect when compared with the control emulsion and the untreated skin. Phospholipids were isolated by dialysis from virgin oil and added to the refined oil (234 ppm). The moisturizing effect obtained with the emulsion containing the enriched refined oil was shown to be the same as that obtained with the virgin oil emulsion.