摘要：5-Aminolevulinic acid (ALA) is a natural amino acid that is used as a raw material for the biosynthesis of red-blood-cell hemoglobin in humans and animals. ALA is the subject of research in a wide range of human health care fields, including skin care and medicine. This study investigated whether and to what extent cosmetics containing ALA (skin lotions and creams) improved facial-skin condition in women. As such, a double-blind controlled experiment was conducted among 45 women aged 47.0 ± 1.72 years. Participants were divided into two intervention groups, including those who used cosmetics containing ALA (C-ALA, n = 22) and those who used cosmetics without ALA (W-ALA, n = 23). Specifically, participants were instructed to use their assigned cosmetics twice per day (morning and evening) after washing their faces before each application. Inner skin condition and skin-water content were evaluated via VISIA-Evolution and Multi Display Devices at baseline and after four and eight weeks of use. The experiment lasted for a total of eight weeks. A baseline comparison at week four showed that skin moisture content increased significantly for the C-ALA group (p = 0.021). Further, wrinkling significantly decreased at week four among participants in the C-ALA group who were evaluated as having many wrinkles at baseline (p = 0.034). These findings suggest that cosmetics containing ALA have moisturizing effects and reduce wrinkling caused by dryness.
