Sensitive skin may be characterized by barrier function alteration, oxidative stress and inflammation all linked together, and exacerbated by external aggressions, such as pollution and UV. The aim of this study was to demonstrate the in-vitro and in-vivo efficacy of an active complex in this vicious circle.
Reconstructed human epidermis were treated (or not) with lactic acid for 4 hours. Then an excipient cream containing or not (placebo) the complex (red sage polyphenols, tetrapeptide-10, carnosine, tocopherol) were applied twice before exposition or not to pollution (dust 100 μg/ml) and UVA (9 J/cm²). Intracellular oxidative stress (H2DCF-DA), lipid oxidation (MDA), skin barrier function (corneodesmosin staining), and inflammation (ELISA IL-8) were assessed 24 hours after. In a 28-days clinical study, 33 women (mean age 42) living in a polluted urban area (China) were included with facial sensitive skin self-reported according to BoSS score and redness. They applied a cream containing the complex twice daily. Soothing and moisturizing effects, TEWL, pH, subjective efficacy and safety were assessed.
The intracellular and lipidic oxidative stresses induced by pollution/UVA were significantly reduced by the complex vs. the non-treated exposed control, -75% and -56%, respectively, and corneodesmosin was significantly preserved IL-8 was similarly inhibited by -19% and -18% with the complex vs the control whether RHE was treated with lactic acid alone or overstressed with pollution/UVA. In vivo, the moisturizing effect immediately after a single cream application (+37%) was still significant at D28 (+22%) associated with an increase of the soothing effect (redness -42%). At D28, the skin was protected, and subjects coped more easily with urban pollution (-46%). A very good appreciation and safety were observed for all subjects.
By preventing skin from oxidative stress, barrier alteration and inflammation induced by pollution and UV, this new active complex preserves sensitive skin from daily aggressions.
