Measurements of skin elasticity and slip; Applications in efficacy substantiation.

Abstract

The purpose of this study was to develop instrumental methods for in vivo measurements of skin elasticity and slip for characterizing skin conditions and substantiating cosmetic efficacy. The bio-rheological instruments developed for this purpose were designed to measure responses eguivalent to the sensory perception by the cosmetic users.For skin elasticity, the instrument measured swelling height of the skin placed under a suction cup with variable pressure. The slip resistance was measured by a reciprocating pick-up probe placed on the skin under a constant pressure.Using the “Skin Elastomer”, we measured the surfaces of facial parts, finger tips and the innerside of the forearms. The “Skin Age Parameter” which indicates recovering power showed a good correlation with the age. Skin rheograms made before and after the use of a facial mask also showed interesting differences under initial pressure.Using the “Skin Slip Resistance Meter”, we quantitatively measured slip resistance on different skin surfaces treated with various cosmetics including toning lotion, creams and studied their effects with time.