Effects of 1,3‐propanediol associated, or not, with butylene glycol and/or glycerol on skin hydration and skin barrier function

Abstract Objective This study aimed to assess the effect of 1,3‐propanediol at different concentrations (5%, 10%, or 15%), either applied alone or in combination with butylene glycol (BG) (5%) and/or glycerol (5%), on skin hydration and skin barrier function. The measurements were conducted using capacitance to determine skin hydration and trans epidermal water loss (TEWL) rates to evaluate skin barrier function. Methods A total of 30 healthy female subjects participated in the study. Capacitance and TEWL measurements were conducted at multiple time points, including before application and at 15 min, 2 and 8 h after the humectants were applied to the forearms of the subjects. All the subjects provided written informed consent. Results The 1,3‐propanediol in all concentrations and in all combinations (with BG and/or glycerol) increased skin hydration and improved skin barrier function 15 min, 2 and 8 h after application. Glycerol increased the hydration performance of 1,3‐propanediol. The application of 1,3‐propanediol at a concentration of 15%, either alone or in combination with other humectants, reduced the TEWL to a greater extent than lower concentrations of 1,3‐propanediol. Furthermore, the addition of glycerol to 1,3‐propanediol 15% improved the skin barrier and reduced TEWL when compared with 1,3‐propanediol alone and with the combination of 1,3‐propanediol + BG. Conclusion The humectants significantly improved skin hydration and reduced TEWL throughout the 8‐h time course. The increase in 1,3‐propanediol concentration, as well as its combination with glycerol, provided a greater benefit to the skin, improving both hydration and the skin barrier function.