The common amphoteric surfactants used as cleansing agents include cocamidopropyl betaine, cocoamphoacetate and cocoamphodiacetate.
Particularly, one of the most common cleansing agents among this group is cocamidopropyl betaine. As its moderate irritancy potential, cocamidopropyl betaine is increasingly used in shampoos and liquid cleansers since its introduction in the 1970s. This surfactant is also considered as a viscosity builder and foam booster.
The reasons for this wide utilzation of amphoteric surfactants are their good cleansing power and lather characteristics, a moderate antimicrobial activity, the lack of toxicity and compatibility with different pHs, in spite of its nonnegligible final cost.
Typical anionic surfactants used as cleansing agents include soaps containing carboxylate ions and synthetic surfactants, mostly alkyl sulphate, alkyl ethoxy sulphate, acylglutamates, alkyl taurates and alkyl sulfosuccinates.
For example, sodium lauryl sulphate (SLS) is a well-known alkyl sulphate which is widely used in personal care products as cleansing agent. Sodium laureth sulphate (SLES) is the favourite primary surfactant in body wash/shower gel and shampoo, because of its good cleansing power and its low cost, even if it has some irritant potential. Actually, new mild cleansers, such as sodium cocoyl isethionate, are marketed.
According to recent studies, alkyl sulphates and alkyl sulfosuccinates have the highest cleansing power, followed by very expensive acyl glutamate and triethanolamine soaps.
Alkyl polyglucosides, such as coco glucoside, lauryl glucoside, decyl glucoside, are among the most common used non-ionic surfactants. Another common non-ionic agent is cocamide DEA (coconut diethanolamide) which is widely used in personal care products.
It is commonly considered that non-ionic agents are the lowest irritants to skin among the different types of surfactants. And non-ionic surfactants alter the cutaneous lipid layer more than anionics, because they can solubilize fatty acids and cholesterol in skin. While their cleansing power and lather characteristics are quite weak, and they are also the most expensive surfactants.
Furthermore, the members of this group have a relatively low potential toxicity and they are considered the gentlest surfactants.