- 日本香粧品学会誌 (ISSN:18802532)
- vol.41, no.2, pp.113-118, 2017-06-30 (Released:2018-06-30)
Continuous use of sunscreen products prevents not only sunburn or suntan, but also signs of photo-aging such as wrinkles or pigmentation spots. In the U.S., sunscreen products are categorized as over-the-counter drugs. If certain conditions are fulfilled, statements on the preventive efficacies against skin cancer and early skin aging are allowed on the package insert. The EU commission also stated “sunscreen products can prevent the damage linked to photo-ageing.” Application of sunscreens is strongly recommended for the prevention of photo-aging or skin cancer in these countries. However, statements on the preventive effects of sunscreen cosmetics against photo-aging or skin cancer are not approved in Japan because their efficacies in Japanese people are unclear because of the lack of reliable data. This article reviews the studies that demonstrated the preventive effects of continuous application of sunscreens on photo-aging, and also describes our three-year study on sunscreen application for Japanese elderly subjects, which is probably the first long-term, interventional, clinical study conducted in Japanese people. The results of our clinical study showed that continuous application of the appropriate amount of sunscreen prevents photo-aging signs such as a change in skin color tone uniformity, similar to that seen in Caucasians. Our study investigating the relationship between efficacy and the amount of sunscreen applied, in order to examine the appropriate use of sunscreens to achieve a sufficient effect, is also introduced here.