j. Soc Cosmet. Chem., 47,299-305 (September/October 1996) Study of skin properties of the face and neck of young Taiwanese women WEI-JING HUNG and GINGER LEE, Department of Cosmetic Science, Chia-Nan College of Pharmacy and Science, Tainan, 717, Taiwan, R.O.C. Accepted for publication September 3 O, 1996. Synopsis The skin characteristics of Oriental people have not yet been well studied. In this study, forty-nine young Taiwanese women from 19 to 23 years of age were the subjects of a test using a sebumeter and a corneome- ter to measure lipid content and moisture content of the facial skin at a temperature of 22-25øC and at a relative humidity of 70-75%. The lipid content was in the range of 4-254 p•gcm -2, and the moisture con- tent was in the range of 23-147 a.u. (arbitrary units). The results show that the skin can be classified into the following types: oily skin (20%), oil-depleted skin (10%), oily T-zone combination skin (22%), and partially oily combination skin (48%). The moisture con- tent of the skin depends more on the location on the face, rather than on the amount of oil secretion. Thus, the skin type is mainly determined by lipid content. Both the lipid content and moisture content of the neck were examined in this study. Oily skin types were found to have the highest lipid content, and lipid-depleted skin types had the lowest lipid content for both front and rear regions of the neck. INTRODUCTION Most skin-care products in Taiwan are imported from other countries, such as France, the U.S., Germany, Japan, or Italy. Taiwan has become a very important cosmetics mar- ket of the world, and mainland China is expected to become an important cosmetics market as well. However, there is not much understanding of the skin properties of Ori- ental women. Human skin is a very complex structure that varies very much with age, temperature, humidity, sex, race, ... etc. Even smoking can dramatically affect skin quality (1). A wide range of cosmetic products have been developed to maintain or improve the con- dition of human skin, including, for example, soapless cleansers and super-fatted soaps. Usually skin type is divided into dry skin, normal skin, combination skin, and oily skin (2,3). Skin type is indicated by the appearance of pores and facial lines. Oily skin tends to have none or fewer facial lines and enlarged pores, while dry skin tends to have more facial lines and almost invisible pores. A better way to determined the skin type is to measure experimentally the oil secretion. Four squares of thin paper are pressed tightly 299

300 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS against the forehead, cheek, chin, and the top of the nose separately for five seconds (4). Then the test papers are examined carefully by eye to evaluate the skin type, since the oil residue will make the test papers translucent. However, oil secretion alone cannot determine the skin type. Both lipid content and moisture content are required. Nogueira and Gabrielle classified skin into six types: oily skin, normal skin, oil-depleted skin, oily dehydrated skin, dehydrated skin, and oil-de- pleted dehydrated skin (5). However, they ignored the combination skin type. Other measurements of skin properties are moisture transmission, viscoelastic response, ultrasound properties, electrical properties, and facial line counting (5-12). Changes in these skin properties are very useful in evaluating the effectiveness of skin care products. Most young Taiwanese women start to apply skin care products around age 20, at which time the skin is supposed to be in its optimum condition. However, there is not much understanding of the skin type of young Taiwanese women, nor of the skin properties of the neck. The purpose of the present research is to study the skin characteristics of face and neck for young Taiwanese women. The results should be helpful for the cosmetic industry in producing skin care products suitable for Oriental people. EXPERIMENTAL The lipid content and moisture content of the skin of forty-nine young Taiwanese women, from ages 19 to 23, were measured at a temperature of 22-25øC and a relative humidity of 70-75%. They were required not to apply any cosmetic products before the test. The measurements were made two hours after their faces were washed by water. Each face was divided into 12 sections and the neck into two sections, as follows: Sections of the face 1. Forehead 2. Side of the eye (R) 3. Side of the eye (L) 4. Under the eye (R) 5. Under the eye (L) 6. Upper cheek (R) 7. Upper cheek (L) 8. Lower cheek (R) 9. Lower cheek (L) 10. Top of the nose 11. Under nose/upper lip 12. Chin Sections of the neck 13. Fore neck 14. Rear neck MEASUREMENT OF LIPID CONTENT The lipid content of each section of face and neck was measured using a sebumeter (Courage and Khazaka Electronic GmbH, Germany). A piece of matted plastic film was pressed against the skin with a force of 4 N for 20 seconds. The measured area was 64 mm 2. Absorption of lipid made the plastic film transparent, which was analyzed by photomerry. The results were evaluated by a microprocessor and transferred to a digital instrument so that the final data could be indicated digitally.