In most dry skin conditions such as psoriasis and cracked skin around the heels there is a deficiency of urea in the epidermis. Urea creams are very effective at helping to re-hydrate the skin because of this. The different urea creams come in different concentrations and preparations and have differing effects depending on that concentration.
At around 40% concentration of urea it is more keratolytic and can be used under occlusion on dystrophic and fungal nails to help “dissolve” the damaged nail.
At above 20% it still does have some keratolytic effects and is good to help get rid of the dry and flaky skin that occurs in many conditions.
At concentrations below 20% of urea it is at its best to restore the levels of urea in the dry skin and re-hydrate it to make it soft, flexible and supple.
There is not one best concentration of urea that makes a good foot cream. The best concentration is the one that matches the effects needed for a particular individuals foot problem.