Anatomy of a Skin Cleanser: Cleansing Ingredients
Cleansers are designed to remove oily soils, dirt, sweat, and sebum from skin through the action of surfactants. Components of surfactants can bind to stratum corneum (SC) proteins, resulting in diminished ability of the SC to bind and hold water. Continued use of products formulated with harsh surfactants can dry skin and promote skin barrier damage, leading to erythema. Anionic surfactants are often used in cleansers because of their excellent ability to foam and lather.
Frequently, amphoteric surfactants are used in combination with anionic surfactants in liquid cleansers because formulators consider amphoteric surfactants to be substantive to skin and act as skin conditioning agents while boosting foaming of the product. While synthetic surfactants are considered mild, impurities and changes in the synthesis of the material can alter irritation potential. Incorporation of nonionic, amphoteric, and cationic surfactants in a single formulation can further reduce the mildness of the anionic surfactant. Proteins, gums, and polymeric ingredients may help reduce irritation potential.
Surfactants are classified by their charge on the surface-active moiety:
- Anionic (dissociation occurs in a negatively charged ion-anion)
- Cationic (a positively charged ion is the carrier of the surface active properties)
- Zwitterionic — commonly known as amphoterics (both positive and negative ions)
- Nonionic (do not dissociate into ions in solution; commonly used in baby products; tend to suppress foam)
