218 JOURNAL OF COSMETIC SCIENCE ELLIPTICALLY OF BODY HAIR AND How To MEASURE ITS APPARENT DIAMETER F. Anthony SimioW, Ph.D., Pamela S. Wit• l, Matt Klein I and Sidney Hornby 2 •Andrew Jergens, Cincinnati, Ohio 2Mar-Tech Contract Services, Broomall, PA Humans grow hair on many parts of their bodies. The amount and density of the hair varies as a function of age and gender. Indeed within an individual the hair at different body sites is not the same. There are differences in how steroid hormones effect the growth cycle, and as will be discussed below, differences in the shape of the hair. This presentation will focus on: 1. Differences in hair parameters from different body sites. 2. How leave-on products affect the hairs' cross-sectional profile. 3. How to reproducibly measure the major axis of body hair. For many years the focus of hair research in our industry has been on the care and treatment of scalp hair. Indeed in 2001, U.S. consumers spent $6 billion dollars on hair products (cleansers, conditioners, styling aids and color combined) •. In comparison, shaving and hair removal are much smaller businesses. It has long been known that unlike Asian scalp hair, Caucasian and African- American hair is not circular in cross sectional profile. Published data showing the ratio of major/minor axes for scalp hair for the 3 major ethnic groups is shown below 2: I Major/MinorAxes Ratio I Asian Caucasian I African-Ame1.7:1 1.3:1 1:1 However, when Caucasian scalp hair is compared with other body sites, it appears to be less elliptical and more circular. MajodMinor Axes Ratio: (Mean + SEM [n =] ) Scalp Underarm Leg Male 1.37 + 0.07 (10) 2.48 + 0.14 (10) 2.58 + 0.13 (10) Female 1.38 + 0.03 (50) ND 2.23 + 0.07 (16) ND - Not Determined Hair is frequently treated with 'conditioning' leave-in and 'cleansing' wash-off, products. A priori, we would expect leave-in products to have the larger effect.

2002 ANNUAL SCIENTIFIC MEETING 219 The effects of a leave-in product (a lotion) on hair ellipisicity were assessed in vitro, using a laser micrometer. The hair was measured, and then treated once with lotion. After drying at 30% RH for twenty-four hours, the major and minor axes were reassessed. A second set of hair was treated for 5 cycles of lotion application before the hair was re-measured. Results show that while the lotion causes the hair to swell, the effects are proportionate for both axes and there was no effect on the ratio. Since body hair is highly elliptical, how do you ensure that you can rapidly and consistently measure one axis in situ? Since the hair shaft usually exits the skin at an angle, with the major axis parallel to the surface, we hypothesized that using a Plexiglas plate to press the hair fiat against the skin would enable consistent photography and measurement of the major axis. This was tested experimentally and proven to be the case. Caucasian women allowed their leg hair to grow (no shaving) for 5 days. It was then photographed using a camera fitted with a non-glare Plexiglas plate to press the hair down and to fix the focal length. The diameter of the hair was then measured from the 35 mm photographs by image analysis. Meanwhile the hair was shaved off, collected and the major and minor axes were determined using a laser fiber micrometer. For fifteen of sixteen samples analyzed, there was no significant difference in the major axis measured by the micrometer and the diameter measured by image analysis. Therefore we concluded that the photographic method described, measures the hairs' major axis. This method has the advantage of simplicity, being able to assess many panelists quickly and easy archiving. References: • Kline Report (2002) Manufacturers' Sales. 2 Robbins C. in "Chemical and Physical Behavior of Human Hair, 4th ed., Pub. Springer-Verlag, New York, Inc., pp 426-428 [2002].