Aqueous thickeners that form a hydrogel through swelling in water and that are formulated in lotions and emulsions to enhance their use and stability are available in great numbers. On the other hand, only a handful of ingredients work in oil, where thickeners that can cope with various oils of different properties barely exist. In the current Japanese market, foundations with high water resistance are popular, and hence oil cleansers capable of removing such foundations are generally used. However, with the limited availability of materials that can thicken oils, it is difficult to develop a formulation that can readily enhance the thickening property and use of oil cleansers. In this study, we have developed a novel versatile organogelator which can control the viscosity of many types of oils and can make transparent viscous solutions. We found the key of the chemical design to be the adjustment of the solubility of the organogelator towards oils using the hetero-structure. This novel organogelator can thicken a wide range of oils from hydrocarbons such as liquid paraffin to ester oils such as cetyl octanoate. Its usage can be enjoyed not only in oil cleansers but in a myriad of formulations that are abundant in oil content while imparting new texture and usability.

The sale of cleansing lotions is widespread due to the convenience of removing makeup, which is associated with the empowerment of women. Nevertheless, friction caused by the cotton used with cleansing lotions is easily felt. Against waterproof makeup, the cleansing ability of cleansing lotions was not as high as that of other cleansing products; this property depends considerably on the performance of the surfactant. Hence, it is desirable to design a surfactant capable of combining improved cleansing ability and reduced friction. In this study, polyglycerol fatty acid ester (PGFE) was used; the optimal PGFE was screened by using surface tension as the index, and a stable blending technique was developed for the preparation and functional evaluation of the solution. Regarding the amount of surfactant contained in commercial products, PGFE exhibited a lower surface tension compared with conventional cleansing ingredients. Furthermore, a mixed system of two PGFEs obtained by screening at a specific ratio notably exhibited a lower surface tension compared with that exhibited by a single system, which corresponded with the packing of fellow PGFEs used. Hence, it is desirable to apply the prepared PGFEs with a high cleansing ability. Moreover, the combination of polyol and co-surfactants was considered to be a solution-stabilized technique for PGFEs. The as-prepared solubilized PGFEs exhibited a higher cleansing ability and moisturizing effect as well as lower friction compared with conventional PGFEs.

In order to develop cosmetic products based on the optical properties of the skin of seniors, we investigated the characteristics of skin color and light scattering inside the skin. Color measurements were performed on four sites on the face (lower part of the cheek, cheek center, beside the eye, and behind the chin), and the values of hue, lightness, and chroma in the Munsell space were determined. Four colorimetric values measured from the same person were plotted on the hue lightness dimension and chroma lightness dimension, and the straight line approximating the four points was obtained in each dimension. Focusing on the slope of the approximate line between hue and lightness and comparing between age groups, we observed little change in lightness with changes in hue in the younger age group, whereas, in the senior age groups, the lightness declined when the hue became reddish. The reflection pattern analysis from the slit light irradiation suggests that the decrease of the reduced scattering coefficient inside the skin is related to the lightness decrease.

IGF-1 (insulin-like growth factor-1) has multiple functions regarding cell proliferation and differentiation. In the skin, IGF-1 is known to have the promoting effect of keratinocyte proliferation, the accelerating effect of collagen production and the inhibitory effect of collagen degradation in fibroblasts. It is well known that the functional expression of IGF-1 declines as the production amount of IGF-1 decreases with aging, but the age-related change on the cells that receive IGF-1 has not been elucidated enough. In this study, we investigated the age-dependent change of IGF-1 function regulating ability in skin cells. The proliferation of aged keratinocytes was not promoted and the change of collagen metabolism in aged fibroblasts was not induced, even when IGF-1 was added to these cells. In addition, the expression level of IGFBP-4 (IGF binding protein-4), which has been reported to suppress the function of IGF-1, was significantly increased in both keratinocytes and fibroblasts with aging. Furthermore, when IGFBP-4 was added to these cells with IGF-1, the promoting effect of keratinocyte proliferation, the accelerating effect of collagen production and the inhibitory effect of collagen degradation in fibroblasts were suppressed. These results suggest that one of the causes of impaired expression of IGF-1 function with aging is a decrease of IGF-1 signaling due to age-dependent increase of IGFBP-4 in the cells that receive IGF-1.

Pasty facial washes are formulated with higher amounts of fatty acid salts and anionic surfactants than those of other washing products, and are associated with higher risks of skin irritation and rough skin. In the present study, we investigated the benefits of facial washes with lower fatty acid contents and the formulation of pasty facial washes with lower fatty acid contents. The results obtained demonstrated that washing with 18% potassium myristate prevented significantly more reduction in moisture content than did 30% potassium myristate. In order to formulate pasty facial washes with an 18% fatty acid content, appropriate thickening polymers were screened. We found that a particular acrylates/C10-30 alkyl acrylate crosspolymer with higher thickening efficiency and salt tolerance thickened the system most efficiently among the polymers studied. A pasty facial wash with an 18% fatty acid content thickened by this polymer significantly prevented reductions in the moisture content of the stratum corneum more than that with a 30% fatty acid content. For confirming the usability of the facial wash, a panel test was performed, and the result showed that the facial wash provided a satisfactory usability to the panelists concerning the pasty facial wash’s basic characteristics such as the volume and the elasticity of foam. These results demonstrate the potential of pasty facial washes with lower fatty acid contents thickened by this polymer as a new generation of soap-based facial washes providing several benefits such as mildness to the skin and cost effectiveness.

The facial skin of men has a large quantity of sebum, but is dry and coarse compared with that of women of the same age. Men’s skin shows a specific aging change in which the skin color becomes dark red with aging. We regard men’s shaving customs to greatly influence this. So we investigated 4 male groups, in their 20s and 50s, who have only used injector razors or who have only used electric shavers every day for a long period of time, and examined the long-term effects of shaving customs on the skin by performing a skin measurement. By carrying out a questionnaire survey of skin conditions and skin care, we considered the relationships among aging of the facial skin of men, shaving and skin care. As a result, when the skin of men in their 50s was compared with that of men in their 20s, the 50-year-old became red-black and much more pigmentation was observed from the cheek to under the chin. These indicate the extent of the damage from shaving. On the other hand, according to the questionnaire survey, there are many men who neglect skin care, including ultraviolet ray countermeasures. As a result of long-term “shaving customs” and “neglect of skin care”, we could conclude they bring about these aging changes peculiar to Japanese men’s facial skin.

Recent research shows that age perceptions from dynamically moving faces are judged by (1) the appearance of the cheek and (2) the dynamic characteristics, such as the fluctuations of “overexposed area” and “the amount of fine linear structures area around the pore”, which increase with aging (77th and 78th SCCJ conference). This study attempted to develop a makeup product which was able to change the age impression, by improving the appearance of dynamically moving cheek. First, this study designed a makeup layer that reduced the fluctuations of the “overexposed area” and “the amount of fine linear structures area around the pore” appearing on the moving cheek. A polymer film, which was flexible enough to follow the dynamically moving skin, and a high optical diffusion particle were selected by an in vitro screening method with artificial skin with pores. Then, a makeup sample prepared with the flexible polymer and particle was applied to the face, and the improvement of the appearance of the moving cheek was evaluated. As a result, the designed makeup layer was able to reduce the fluctuations of the “overexposed area” and “the amount of fine linear structures area around the pore”. The flexible polymer was speculated to hold the high diffusion particles uniformly even in a dynamically moving condition, resulting in the improvement of the perceptual appearance of dynamically moving face that increases with aging.