Your choice of product should depend on the level of dryness of your skin and the symptoms you experience. If your skin is dry and rough then 5% Urea should be a sufficient concentration to provide immediate and long-lasting relief. If your skin is very dry then a higher, 10% concentration of Urea will be more suitable for immediate relief and for delaying symptoms for up to 48 hours. If you are in any doubt, we recommend you ask a pharmacist or dermatologist for advice.