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Formulas Deciphered: Facial Wash
By: Eric S. Abrutyn, TPC2 Advisors Ltd., Inc.
Posted: October 29, 2010, from the November 2010 issue of Cosmetics & Toiletries.
Editor’s note: Complementing his regular “Anatomy of a Formula” column that explains how to build formulas from individual ingredients, Eric Abrutyn now takes a top-down approach by breaking commercial products down to examine their individual components in this new column, “Formulas Deciphered.”
Facial washes, offered either as clear liquids or opaque base creams, have been around for some time. The primary performance characteristics include: a creamy lather with some level of foam that spreads without dripping, exhibits low irritation, imparts a soft/silky after-feel, is non-drying and is easy to rinse off. In the case of facial wash, it is appropriate to reduce the surface cleaning properties so as not to strip away desirable lipids on the skin surface.
The surfactant system is the key building block to any facial wash. This system is comprised of anionic, cationic, nonionic and amphoteric surfactants. Anionic surfactants such as carboxylic acid, sulfates, sulfonic acids and phosphoric acid derivatives are incorporated for their surface activity and have negatively charged polar head groups. Cationic surfactants have positively charged polar head groups, such as amines, alkylimidazolines, alkoxylated amines and quaternary ammonium. These materials are used for their substantivity and electrostatic attractive properties to skin.
Nonionic surfactants, which have no charge, are incorporated into facial washes as emulsifiers, conditioning agents and solubiliziers/coupling agents. These surfactants have a diverse representation, including alkylene oxides, polyglucosides, fatty alcohols, ethanolamines and dimethylamine oxides. Finally, amphoteric surfactants are used in facial care washes as secondary surfactants to help boost foam, improve conditioning and reduce irritation. They are zwitterionic and can be positively or negatively charged, depending on the pH of their environment.
Besides the surfactant system, other important components in a facial wash are stabilizers such as fatty alcohols, emollients and moisturizers including glycerin, fatty acid esters and polymers, rinse-off aids, chelating agents, pH adjusters, viscosity modifiers such as salt and gums, UV stabilizers for colorants, and antioxidants.