Facial oiliness and dryness: Correlation between instrumental measurements and self-assessment

The facial skin of many individuals is excessively oily in some areas, excessively dry in others. Skin care products for general use thus need to be compatible with both oily and dry skin. Formulating such compatible products requires accurate, objective assessment of oiliness and dryness in vivo. Oiliness is assessed by measuring skin surface friction; this characteristic varies on different parts of the face, and it may be altered by product application. The forehead and nasal fold areas were found to be oilier than the cheeks, and an inverse relationship was shown between perceived oiliness and skin surface friction. Drying effects are assessed by measuring the increased stiffness (tautness) of the stratum corneum which may result, for example, from ordinary washing with soap and water, or from application of products which have a drying effect on the skin. Changes in skin surface stiffness are more readily demonstrated on the cheeks than on the forehead, although baseline stiffness is found to be greater on this (latter) site. In this assessment, we use a gas-bearing electrodynamometer suitably adapted for measurements on the face. Objective measurements made with these instruments correlate well with self-assessment of facial oiliness and dryness