Shampoos: ingredients, efficacy and adverse effects.

Shampoos are the most frequently prescribed treatment for the hair and scalp. The different qualities demanded from a shampoo go beyond cleansing. A cosmetic benefit is expected, and the shampoo has to be tailored to variations associated with hair quality, age, hair care habits, and specific problems related to the condition of the scalp. The reciprocal relationship between cosmetic technology and medical therapy is reflected in the advances of shampoo formulation that has made applications possible that combine benefits of cosmetic hair care products with efficacy of medicinal products. A shampoo is composed of 10 to 30 ingredients: cleansing agents (surfactants), conditioning agents, special care ingredients, and additives. Since the cleansing activity depends on the type and amount of surfactants utilized, shampoos are composed of a blend of different surfactants, depending on the requirements of the individual hair type. Development time from the concept to the commercial shampoo may take longer than a year. Much effort is invested in the development of conditioning agents, which impart luster, smoothness, volume and buoyancy. Another prerequisite is a scalp free of scaling. Current anti-dandruff agents primarily have an antimicrobial mode of action, and inhibit growth of Malassezia spp. Recent developments in shampoo technology have led to increased efficacy of anti-dandruff agents, allowing shorter contact time, and reducing irritation.