The skin mainly intends to protect human beings against environmental aggressions.
It fills this “barrier” part through a complex structure whose external part is made up by the stratum corneum—a horny layer covered with a hydrolipidic protective film. This function is only ensured when this horny layer made up of the accumulation of dead cells is properly moisturized as the water is the keratin plasticizer.
The underlying epidermis also enables to reinforce the skin’s defense capacity by
ensuring the continuous and functional regeneration of the surface state (keratogenesis) and skin pigmentation (melanogenesis).