ABSTRACT
INTRODUCTION Evaluation of the surface structure and functional properties of the skin for the purpose of making claims on the efficacy of skin care products is a key part of cosmetic product research and development. Other parts of this book have dealt with structure and properties of the skin. This chapter will deal with instrumental and expert methods to evaluate skin as used by the cosmetics industry. The principles governing clinical trials in the consumer products industry are much the same as in therapeutic drug clinical trials. Thus, safety and ethical clearance of products, procedures to be used, investigator training, and monitoring and auditing of trials are considered important for both the safety of the subjects enrolled into trials and for the validity of the results obtained. Choice of subjects, skin properties, ethnicity, age, sex, absence of other confounding factors, disease, drug ingestion, etc. that will invalidate the results are taken cared of by careful crafting of inclusion and exclusion criteria.
