Beautiful and healthy hair is desired by many women. However, hair texture and appearance are easily affected by various kinds of damage in daily life such as hair coloring, perms, ultraviolet light, shampoo and/or aging. Therefore, damage care and aging care for hair is important, and the development of these new technologies is strongly required. In this paper, we discuss our recent two studies that provide solutions for hair damage and aging. One is suppression of the dullness of hair color due to melanin elution from hair by shampoo. The other is the technology for improving hair stiffness and resiliency by increasing the expression of keratin-associated protein 5 (KAP5), which is specifically expressed in the hair cuticle.

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Currently, there is high demand for sun-care products. Among them, loose powder type products have excellent characteristics such as ease of reapplication and natural complexion finish. Therefore, we focused on the development of loose powders with a high UV protection. In order to obtain loose powder products with a high UV protection and an excellent texture, it is desirable to incorporate inorganic UV scattering agents and organic UV absorbers into the formula in the appropriate balance. However it is unusual for loose powders to contain an adequate amount of UV absorbers to achieve high UV protection because of problems such as caking and agglomeration. In this study, a loose powder with both high UV protection and good texture was developed by using petal-like calcium silicate (P-CS). The optimum particle size of P-CS was evaluated in terms of oil absorption value and texture. In addition, P-CS with a particle size of 9 μm was broken apart by a light rubbing force and the absorbed oil in the P-CS particles was released and spread across a broad area. This mechanism is considered to be essential to the enhancement of UV protection. Finally, we accomplished an innovative loose powder with both extremely high UV protection and an excellent texture and usability by utilizing these effects.

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This study considered the relations between appearance age, real age, skin state, facial proportion, physical index, skin impression and attractiveness impression for women in their 30s and 40s. As a result, it was shown that there is a difference of about 20 years in appearance age in women whose real age differed by only 4 years and also that the appearance age is influenced by the wrinkles of the eye area, pigmented spots, and sagging of the skin. For women in their 40s, there were relations with perceived age and the flexibility of skin and also with the amount of sebum. Moreover, although there was no relation between appearance age and facial proportion or physical index, there was a strong relation between skin impression and attractiveness impression. The appearance of women in their 30s and 40s varies greatly among individuals. The results indicate that the condition of their skin, rather than the facial proportion, strongly influenced the perception of appearance age. Moreover there are differences in the factors and the degree of influence that each factor has upon appearance age, between different age groups.

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The phospholipid is known to be safe and have superior tactile sensation, as well as to have the ability to improve the skin penetration of active ingredients, and it has been reported that the fact that the hydrophobic group of phospholipid is made of unsaturated fatty acid plays an important role in this process. However, the correlation between the membrane-fluidity of hydrophobic group and stratum corneum (SC) penetration has not been examined in detail. Therefore, in this study, we focused on the characteristics of phospholipids, and evaluated the correlation between membrane-fluidity and SC penetration. We also evaluated the interaction between liposomes and SC lipid liposome, and verified the mechanism of SC penetration. First, we created different types of liposomes: DPPC, whose acyl is made of saturated fatty acid; DOPC, which is made of unsaturated fatty acid; POPC, which has both saturated and unsaturated fatty acid in one molecule and a lipid component (DP+DO) which is mixture of DPPC and DOPC with molar ratio of 1: 1. As we examined the correlation between membrane-fluidity of the hydrophobic group and SC penetration of the water soluble component that coexists with membrane-fluidity, we found that POPC and DOPC, whose membrane-fluidity is high, have high SC penetration, and DPPC, whose membrane-fluidity is low, has low SC penetration. As we moved on to evaluating the influence that each phospholipid has on the membrane-fluidity of SC lipid liposome, correlation with the membrane-fluidity of the hydrophobic group of each phospholipid was indicated, and POPC showed the highest level of influence. These results suggest that as for SC penetration, even though unsaturated fatty acid of the phospholipid is a significant factor, the structure in which unsaturated and saturated fatty acid exist in the same molecule and stand alternately in membrane formation, like that of POPC, effectively changes the membrane-fluidity of SC lipid liposome, and accelerates SC penetration.

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In the development of hair styling products, hair setting strength and holding ability are very important functions. Humidity is known to have the worst influence on these functions. We previously revealed that scalp sebum transferred to the hair and had adverse effects on both setting strength and holding ability. In this study, we examined the influence of scalp sebum on hair setting strength and the transfer rate of scalp sebum to hair in a high-humidity environment. The transfer rate of scalp sebum to the hair increased with high humidity and the sebum decreased hair setting strength to a lower level than that caused by highly humid conditions alone. It is conventionally believed that moisture is the sole factor that decreases hair setting strength and holding ability under high humidity. However, our results suggest that not only moisture but also scalp sebum decrease the hair setting strength under highly humid conditions.

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