Oneof the most important prerequisites of healthy skin is the intactness of its lipid permeability barrier--a unique stack of bilayers assembled in the epidermis from a mixture of biomolecules. But topical formulations that include emulsifiers attach that barrier.
The function of emulsifiers in skin care products is to disperse lipids contianed in the formulations. However, when these emulsifiers disperse lipids of the permeability barrier, the continuous stacked-bilayer structure is either damaged or destroyed. The extent of the interaction is the function of the emulsfiers' chemical structure and dosage in a given products.