Formulation Technology and Efficacy from Making Wrinkles “Inconspicuous” to “Improving” Wrinkles

Abstract

In a life lasting 100 years, wrinkles, which can be said to be the annual rings of life, will inevitably increase as a central skin concern. For this review, in describing how cosmetics (quasi-drugs) can contribute to the problem of wrinkles, we describe powder formulations that make wrinkles inconspicuous, and discuss the effectiveness of active ingredients to improve wrinkles and their impact at the cellular level. Foundation, which is based on powder formulation technology, has traditionally functioned well for the shape correction of shallow skin roughness, such as with pores. However, until this study, it could not be said that effective solutions existed for the shape correction for deep skin roughness, such as with wrinkles. By means of a Monte-Carlo-based optical simulation, we have elucidated why it is not possible to make wrinkles inconspicuous with normal FD application. Furthermore, we were able to realize a novel formulation with a shape correcting function that can make wrinkles inconspicuous. In 2016, for the first time in the quasi-drug category, an “improvement of wrinkles” appeal was approved due to its effectiveness, according to the guidelines. Until then, the appeal for wrinkles in Japan was far behind in comparison with the global cosmetics industry, but this was eventually harmonized with international standards. To prove the effectiveness, we conducted a retinol efficacy test. The retinol-containing formulation and a placebo formulation (retinol-extracted) were continuously applied on half the face and around the eyes, centered on the corner of the left and right eyes, for 9 weeks. In the evaluation of both visual judgements and instrumental analysis (replica analysis), based on the exacting guidelines of the Japanese Cosmetic Science Society for evaluating anti-wrinkle products, in a randomized placebo-controlled, double-blind study, the side receiving the retinol formulation experienced significantly reduced wrinkles compared to the placebo formulation side. Therefore, according to the guidelines, retinol was found to be effective in improving wrinkles. After many years of rigorous examination, retinol was approved by the Japanese Ministry of Health, Labour and Welfare in 2017 as an active ingredient that “improves wrinkles” in the quasi-drug category. From the experiments using normal human epidermal keratinocytes, retinol enhanced the gene expression of hyaluronic acid synthase, HAS3, and significantly produced hyaluronan. It is thought that such an action to promote the production of hyaluronic acid significantly improves the skin water content and improves wrinkles by providing flexibility to the skin.