In this study, we propose a new skin approach which aims to improve the quality of life (QOL) of the skincare users. In order to improve their QOL through skin care, it is essential to design the cosmetic products considering scenes in the users' lifestyles in addition to the conventional improvement of the skin condition. Therefore, we focused on the busy working women whose number is recently increasing and observed their skin conditions. In this paper, we introduce skincare technology based on the busy working women's skin conditions and lifestyles.

Hyaluronic acid (HA) is renowned for its excellent moisturizing properties, demonstrating remarkable potential for preserving youthful and vibrant skin. Our previous study using magnesium chloride hexahydrate (MgCl₂) -incorporated HA (HA-Mg) demonstrated significantly improved penetrability of high molecular weight HA into the stratum corneum (SC). However, the effects of this penetration beyond simple moisturization remain unexplored. In addition, the presence of MgCl₂ reduced the bound water near the HA molecules, thereby affecting their moisturizing capacity─an observation attributed to the shielding effect on carboxyl groups. In this study, we engineered a new method aimed at improving the moisturizing effect of HA-Mg after topical application and clarified the usefulness of SC-penetrated HA. SC viscoelasticity and transparency were measured using a dynamic viscoelasticity device and haze meter, respectively. Next, the effect of chelating agents on specific volumes of HA-Mg molecules was investigated. While bound water contents were measured using a differential scanning calorimeter (DSC), the effect of chelating agents on the moisturizing effect of HA and skin texture were assessed using a Corneometer^® and digital microscope, respectively. HA-Mg application resulted in reduced SC elasticity but increased transparency. MgCl₂ addition induced a decreased HA's specific volume, whereas adding chelating agents, particularly sodium metaphosphate (SMP), yielded an improved HA-Mg's specific volume. DSC measurements showed increased bound water content in HA-Mg upon SMP addition. In addition, post-HA-Mg application, in vivo SMP treatment yielded elevated SC water content and a young-like uniform skin texture. Overall, this approach can noninvasively introduce natural HA into the skin without compromising its effectiveness while supporting youthful skin in daily care.

Dry skin is a common skin condition in winter that most often develops on the lower legs in older adults. This study aimed to explore the potential of a formulation containing 1-ethyl-β-N-acetylglucosaminide (β-NAG2), a newly developed epidermal hyaluronan (HA) inducer, to improve dry skin conditions. Twenty-four healthy older adult Japanese subjects participated in a single-arm pilot clinical study conducted from January to March in 2021 in Japan. The subjects topically applied a formulation containing 3.5% β-NAG2 to the outer calf of the leg for 6 weeks, and skin characteristics were observed at weeks 0 (baseline), 4, and 6, and after a 1-week regression phase (week 7). We found that the β-NAG2-formulated lotion significantly improved the visual dryness score and increased hydration in the stratum corneum (SC). These changes may not be solely due to the SC moisturization by the formulation, but could also be due to increased hydration in the deep skin tissue below the SC. This formulation also significantly improved the visual scaliness and SEsc values. Normalized desquamation and increased epidermal turnover caused by the formulation may improve skin scaliness. Moreover, the formulation was found to enhance skin elasticity, which was linked to an increase in the tissue water content. Taken together, these results suggest that the β-NAG2-formulated lotion was effective in improving dry skin in older adults. We propose that targeting epidermal HA can be a promising strategy to prevent or remedy dry skin in this population.

The macroscopic structure of the film forming polymers utilized in cosmetics can be roughly classified into three categories: linear, branched, and particulate, and the degree of intermolecular interaction differs depending on the structure, resulting in different film properties for each. In addition to this morphology, we need to take into account the chemical structure, a microscopic factor that determines the polarity of the film. In order to develop functional films suitable to specific purposes, we have examined the development of new functions by polymer composites and their applications using these properties. Mascara is one of the formulations in which the properties of the film formers are directly related to the function. In addition to lash curl retention, mascara must have both excellent water resistance and easy rinsability, which are contradictory properties. In order to realize such functions, we investigated a new film-forming technology utilizing the characteristics of originally developed raw materials, and achieved the desired effects by combining an ingredient with amphiphilic properties to form hydrophilic domains in the hydrophobic film to achieve both high durability and excellent curl retention. The amphiphilic polymer plays a role as a trigger ingredient having excellent affinity with water that destroys the film, and also as an ingredient with temperature responsiveness.