The asterisk (3-6) in the Figure 1 is quaternary ammonium salt surfactant, 3: Dimethyldistearylammonium chloride, 4: Trimethylstearylammonium chloride, 5: Lauryl Dimethylaminoacetic acid betaine, and 6: Cocamidopropyl betaine. The TI values of 4 and 5 are high, that is, the effect on the skin barrier function is large. 1 is Sodium laurate which is a common soap. With this anionic surfactant, strong tissue damage is observed by microscopic observation. Figure 2A shows the microscopic observation image of HE stained skin tissue seriously destructed by 1. The outermost stratum corneum of the epidermis is lost, and the adhesion between the epidermis layer and the dermis layer is broken. On the other hand, no skin tissue damage is observed with the quaternary ammonium salt surfactant. Figure 2B shows the skin tissue treated by 5. 2 is Sodium lauryl sulphate, the main component of many neutral detergents. The effect on the skin barrier function is relatively small, but it has injury to the skin tissue.\cite{Kubota_2016}