XERIAL 40 gel is specifically designed to be applied to damaged and thickened nails. It is used in adults and children from 3 years of age. Its formula is concentrated at 40% urea for optimal effectiveness on damaged, broken, and ridged nails. feet. Its applicator brush allows for even application of the gel across the entire nail surface. It can be used una once or twice a day, alone or in addition to a local dermatological treatment.