EUCALYPTUS EXTRACT-INDUCED HAIR CHANGES 485 (Thickness:about 2 J1 m) Measuring Area(6 J1 m2) Medulla Figure 1. Microscope IR measurement. The outer layer (gray) indicates the cuticle, the circle in the center indicates the medulla, and the white area between the cuticle and medulla is the cortex. The gray square means measuring area of IR by the microscopic method. of averaged Young's moduli of the hair fibers of the EL side against that of the PL side was 1.067 ± 0.041 (p = 0.0122, t-test). It can be said that the increase in hair elasticity by the use of EL was significant. Photographs of the root part of the hair on both sides of the head were taken, after natural drying and binding up of the hair of the top part of the head. Figure 3 shows photographs of the head of one panelist, as an example of the difference in appearance after EL usage. In the view from the back (a), the improvement of the stand-up at the root part of the hair can be seen, and in the view from the side (b), the visible scalp at the root of the parted hair on the EL side was noted to be narrower than that of the PL side. The results of the interviews with the panelists after three-month usage are summarized in Table I. More than 70% of the panelists had a good feeling about the change in the physical properties of the hair fibers on the EL side. As mentioned above, it has been confirmed that the panelists sufficiently recognized these changes in hair fiber proper­ ties. Figure 4 shows the difference in hair gloss intensity between the hair fibers treated with the Eucalyptus extract lotions and those treated with the placebo lotion for three months at the root. The results for all panelists indicate that the hair gloss intensity increased at the re-growth part by using the Eucalyptus extract scalp lotion. The total increase in hair gloss intensity was about 10%. In order to confirm the dose dependence of the Eucalyptus extract in the scalp lotion, Els containing 0.5%, 1.0%, and 3.0% Eucalyptus extract were used in the half-head tests

486 flJ .,_ OJ) = = 0 12.0 11.5 11.0 10.5 10.0 9.5 JOURNAL OF COSMETIC SCIENCE p=0.0122 I Placebo Eucalyptus Figure 2. Bending properties of hairs after three months of half-head use test of the continuous application of Eucalyptus extract lotion and placebo lotion (Group 1 ). with Japanese male panelists (ten men for each concentration). The results of the bending stress measurements after 2.5-month usage are shown in Figure 5. As can be seen from Figure 5, the improvement in bending stress by treatment with EL increases as the dose of the Eucalyptus extract increases, from 1.0wt% to 3.0wt%. This indicates that the Eucalyptus extract increased the bending modulus of the hair fibers, a result that was subsequently shown for both males and females. Figures 6 and 7 show the results of the bending stiffness and hair gloss intensity measurements for Group 2. In this test, the concentration of Eucalyptus extract was 3%. In Figure 6, the vertical axis is normalized by the Young's modulus of the hair before using scalp lotion and defined to be (E 2 - E 1 / E 1 ), where E 1 and E 2 are Young's modulus before and after using the Eucalyptus extract lotion, respectively. In the case of hair gloss intensity (Figure 6), the vertical axis is also normalized and defined to be (12 - 1 1 / 1 1 ), where 1 1 and 1 2 are gloss intensities before and after using the scalp lotion, respectively. Six of 17 panelists applied the placebo lotion, and the results for these are also included in Figures 6 and 7. In the case of the placebo lotion panelists, the improvements in hair bending stiffness and hair gloss intensity were not seen after using the scalp lotion. For Eucalyptus extract lotion panelists, on the other hand, the bending stiffness and the hair gloss intensity were found to increase by between 10% and 25% in the older generation