Can a single surfactant both clean the skin and treat it? This article describes the dual functionality of zinc coceth sulfate (ZnCS) that appears to be based on its mildness and its ability to deposit zinc basic salts onto the skin. Divalent salts (usually magnesium salts) of alkyl ether sulfates are known for their skin mildness. ZnCS, obtained by a special synthesis and stabilized as regards hydrolysis, represents a new generation in the fi eld of mild surfactants. It is provided with complex functional properties and a wide potential for special application in skin care.
The reason for such functionality is the same that, in the past, seemed to hinder most cosmetic applications: the easy precipitation of insoluble zinc compounds from anionic surfactant solutions containing zinc ions. Such a drawback represented a hurdle to the wide use of this surfactant in cleansing formulations. Indeed, it is also the key to its special activity in functional skin cleansing.
The ways to stabilize ZnCS solutions and the evaluation of some skin properties after treatment with such solutions are here described. Long-term effi cacy parameters seemed to be related to zinc species diffusion into the stratum corneum. Zinc species deposition onto skin has also been investigated.