Abstract
Facial cleansers, which are mainly composed of fatty acid soaps or surfactants, have some potential to damage skin, depending on their usage. To prevent this undesirable effect, several efforts have been made in designing formulations. Selection of surfactants which have less irritant potency is an example. However, there are some cases in which we could not obtain the expected outcome in practical situations. When using a facial cleanser, consumers change it in shape by themselves ; that is, they make lather in their own way. Focusing on that point, we investigated whether the lather makes an impact on the skin condition. Volunteers were employed for a short-term test to use a standard facial cleanser. They were assigned to two groups ; one group was directed to make good lather in advance, while the other to make it poorly. The amount of product per use and the density of lather, expressed as the mass of total fatty acids per unit volume, were measured. Examination of facial skin was conducted at the end of the test. As a result, those who made good lather didn't show any adverse effect. On the other hand, the others who made poor lather showed a few symptoms of redness, scaling, stinging or itchiness. Based on the result, we conclude that it is important to give more explicit information on the point of usage (i. e. the ideal amount of product per use, adding water into lather, and working with a sufficient amount of air) . We also consider that there is more need to enlighten consumers on that point.
