Previous studies have shown the importance of four factors predisposing to dry skin:
1. the lack of water of corneocytes, directly depending on the presence of NMF;
2. the epidermal hyper-proliferation, resulting from a deficiency in the renewal process of the keratinocytes;
3. the change of lipidic synthesis at cell level; and
4. the deterioration of the functionality of skin barrier, following a degradation of intercellular cohesion.