Hydrating effects of moisturizer active compounds incorporated into hydrogels: in vivo assessment and comparison between devices

Background  Water is an important factor on the appearance and function of the skin and, when dehydrated, it becomes rough and flaky. The measurement of stratum corneum hydration is widely employed to verify the moisture effect of topical products.
Aims  This study has evaluated in vivo the stratum corneum hydration, by the electrical measurements of skin, after treatment with different moisturizers presented in gel base. MoistureMeter® and Corneometer were used as bio-instruments. Urea, the herbal extract ( Imperata cylindrical ), the NMF™ components and the carbohydrate derivate compound (xylityglucoside, anhydroxylitol, and xylitol) were used as the active substances.
Methods  The study protocol was carried out according to the three-factor factorial design. The gels were applied on both forearms of eight female volunteers. However, each volunteer had one untreated skin area as the skin moisture control. The electrical capacitance of the skin was measured by both instruments in different times: after application (0 time), 30, 60, 120, 240 and 360 min.
Results  Gel base, gel containing herbal extract, and gel containing NMF™ components statistically have equal moisture effect measurements, according to both bio-instruments. However, the values obtained for urea, carbohydrate derivate compound, and untreated skin (control) have statically different results in both devices.
Conclusion  The gel containing urea and the carbohydrate derivate compound gel have promoted the most intense moisture effect compared with the other formulations. The measurements of hydration between the devices generated different absolute values; however, the statistical analysis has shown similar precision among the measurements.