According to Women's Health, shampoo is composed of 80 percent water, which serves as a carrier for the many different ingredients that make the shampoo. Most shampoos contain sodium lauryl sulfate, ammonium laureth sulfate or ammonium lauryl sulfate as the main cleaning agent.
The other important ingredients include sodium chloride (salt), which affects shampoo viscosity, glycol distearate or glycol stearate, both of which are waxes that give shampoo a shiny sheen and help it to flow easily from the bottle, fragrances and preservatives. Shampoo contains many other ingredients, each aimed at having a specific effect on the hair.
WebMD says that different shampoos are formulated for specific hair types and advises people to read the label and choose the right shampoo for their hair types. Some shampoo ingredients can cause health problems in users. These include allergens that cause contact allergies and others that may interfere with developing neurons.
Specialized shampoos have been developed to cater for specific user needs. These include: anti-dandruff shampoo, hair-color protecting shampoo, gluten-free shampoo, organic shampoo, baby shampoo and animal (pet) shampoo. Some of the earliest use of shampoo has been in Indonesia and India, where they used ash and water to create a basic soap.