Allantoin is a suitable alternative to urea to hydrate the skin. It originates from a plant metabolite, however today it is synthetically produced. It accelerates the process that causes the skin to loosen dead skin cells, replacing them with healthy new ones. Therefore, it is well-suited for oily, impure skin types. Furthermore, the allantoin is known as having healing, skin smoothing and cell regenerating properties. However, it is not as effective in binding moisture compared to urea.
see Heike Käser 2010, "Naturkosmetische resources", Linz, Freya Verlag, 3rd Edition 2012