186 JOURNAL OF COSMETIC SCIENCE COMPARISON OF FACIAL CHARACTERISTICS OF JAPANESE AND CAUCASIAN SKIN Amy C. Zimmerman, Albert M Kligman, M.D., Ph.D., Ronald L. Rizer, Ph. D, John V. Scimeca, James R. Mayne Amway Corporation, Ada, M149355 INTRODUCTION Traditional safety studies used to develop products have not been predictive of adverse results in the field, due to differences between Japanese and Caucasian skin. The difference between these two populations is centered around the fact that both Japanese dermatologists and the Japanese people perceive their skin to be sensitive. The Japanese population has exhibited more neuro-sensory reactions such as itching, burning and stinging as compared to Caucasian populations. Ordinary safety and use testing does not forecast these differences. The development of products for a global marketplace requires understanding of these differences. If cosmetic scientists are to be successful in formulating efficacious products for the Japanese market, we must first examine the skin characteristics of their populations and their reaction to topical preparations. The challenge for our industry is to determine how to predict and forecast potential problems. MARKETING EXPER•NCE High on the list of consumer complaints in the Japanese market are burning, itching and stinging, especially on the face. Both raw materials used and formulation types have been identified as contributors to these irritation reactions. Problematic Ingredients Problematic Formulation Types Alcohol Highly Occlusive Creams Preservative Systems Some Leave-On Products Fragrances Masks Low Molecular Weight Esters Eye Area Products Organic Sunscreens Another area to consider when marketing products to the Japanese is the fact that there are real cultural differences between the two populations. One area is in preference of product types. The Japanese prefer light products which go on smoothly and which leave little or no residue. Heavy, greasy or oily products are not well received. A second cultural difference is that the Japanese population is typically less concerned with facial wrinkles and lines. A much stronger focus is placed on the clarity, tone and texture of their skin. Minor changes in skin color or mottling of the skin are perceived as a very big problem.

PREPRINTS OF THE 1998 ANNUAL SCIENTIFIC SEMINAR 187 Significant in determining the source of adverse reactions is the cultural differences in skin cleansing. The normal Japanese cleansing regimen includes the use of several products designed to remove makeup, thoroughly cleanse the skin and prepare the skin for moisturization. This cleansing routine is performed two or more times daily. This strong attention to completely cleansing the skin may result in subclinical irritation, thus making the skin increasingly sensitive towards otherwise innocuous ingredients and products. This is a prime example of Dr. Albert Kligman's concept of "Invisible Dermatology". The Japanese skin is already somewhat compromised by the cultural practice of extensive cleansing, so any new product introduced into the skin care regime may experience an unusual number of complaints in Japan. CONCLUSIONS Market experience has shown there are both real and perceived differences between Caucasian and Japanese populations. There is a real difference in the types of products preferred by the two populations, as well as the types of adverse reactions documented for these products. Sub clinical irritation due in part to extensive cleansing routines may play a large part in the increased rate of irritation. Our clinical evaluations have shown many similarities between the two populations, but both directional and statistical differences were shown in several areas. Japanese skin: * does appear to have differences in skin firmness and resiliency * exhibits a decreased level of actinic damage as seen in higher Fitzpatrick scores, and probably a greater photoprotective capacity, due to increased levels of melanin * has fewer fine lines and wrinkles due in part to safer practices regarding reduction of sun exposure exhibits a lower sebum secretion rate, inferring a reduction in acne prone skin possesses lower levels of ceramides I and 2 differs in the skin surface lipid content from Caucasian skin shows apparent differences in microcirculation and blood flow response which may also be an indicator as to why there are variances in product safety studies of consumer test products when evaluated on Caucasian and Japanese panels for sale in the US and in Japan.