The influence of dihydroxyacetone (DHA) contained in the self-tanning lotions with human skin – spectroscopic and theoretical studies

Abstract

The purpose of this study was to investigate selected properties of eight bronzers differing in consistency and dihydroxyacetone (DHA) content. The investigated bronzers were divided into three groups including: liquid sunless tanning products containing DHA level of about 15%, half-liquid self-tanners (spray or foam), and bronzers in the form of a cream. The products from the two latter groups contained about 5% DHA. This study inspected if self-tanners have the ability to absorb UV radiation. The aim of using infrared spectroscopy was to investigate the influence of self-tanners on skin moisture level. During the study, quantum-mechanical calculations were done. The calculations were related to computer-based modeling of DHA permeability through the beta-keratin layer of the skin. The calculations were also done to estimate hydrogen bond energy between chains of the beta-keratin as well as the surface of the crystallized beta-keratin surface. The results indicated that DHA absorbed UV-C radiation very strong, whereas UV-B radiation was absorbed to a lower degree. The least absorbancy was discovered in the UV-A range. Liquid and, partly, half-liquid self-tanners reduced skin moisture; however, products in the form of cream contained moisturizing substances that neutralize the negative effect of DHA on skin hydration. In silico studies indicated that DHA does not permeate through the beta-keratin layer of the skin. Potential reasons for this may be the large energy of hydrogen bonds and charged beta-keratin surface.