The main ingredients in shampoo are water, detergents, preservatives, thickeners and conditioning agents. Some types of shampoo may contain modifiers, special additives or plant extracts.
Water, detergents and preservatives are the main ingredients in all shampoos. De-ionized water makes up 70 to 80 percent of the shampoo formula. Detergents are the cleansing ingredient in shampoo and help to remove oil from hair. Preservatives prevent the growth of bacteria and other microbes in shampoo.
Thickeners, foam boosters and conditioning agents are the secondary ingredients in shampoo. Foam boosters help increase the amount of foam and bubbles. Conditioning agents are added to offset the effect of harsher ingredients on hair. These agents reduce static electricity and improve the softness and feel of hair.
Ingredients that modify the color and scent of shampoo are special additives. Other special additives include botanical extracts, natural oils, proteins and vitamins.
Depending on the type of shampoo, other ingredients are sometimes added. All-natural shampoos use plant extracts and other all-natural ingredients. Alternative shampoos use fewer harsh chemicals.
Cosmetic chemists develop shampoo formulas in the lab. After defining the characteristics of the shampoo, decisions are made regarding smell, color and thickness. Irritation and performance of the shampoo are also considered during formula development.