Chemicals in Shampoos

There are a range of shampoos on the market which vary in their function: from moisturizing to clarifying, to color depositing, and even medicating the hair and scalp. What these shampoos have in common are the general classes of ingredients they contain. By knowing the function of chemicals in shampoo, you can make informed decisions about which products will work for your hair.


Detergents are the active ingredients in shampoo that clean your hair. They bond with the oils on your hair and wash them out. Some of the most effective detergents are sulfates, and most shampoos contain some form of sulfate detergent. Two common sulfates used in shampoos are sodium lauryl sulfate and ammonium lauryl sulfate.

Detergent molecules have two components: a part that binds to oil and dirt, and a part that interacts with water. The detergent molecules surround dirt and oil and lift it off of your hair so it can be washed away with water. The detergents in shampoo are designed so shampoo will not react with hard water, so they will not leave a soap scum buildup in your hair.

Shampoos with higher concentrations of detergent are considered clarifying shampoos, while those with less detergent are generally moisturizing shampoos.


Almost all shampoos contain some moisturizing ingredients to prevent a feeling of stripped hair after shampooing. The moisturizers are generally in the form of fatty alcohols, like cetyl alcohol or stearyl alcohol. Some shampoos also contain silicones such as dimethicone and cyclomethicone, which condition and protect the hair. Other conditioning ingredients, like honey or hydrolyzed proteins, may be present in shampoos, but at such a low level that they do not provide much conditioning.

Clarifying shampoos have few to no moisturizing ingredients, as these shampoos are meant to remove any buildup from the hair. Moisturizing shampoos and 2-in-1 shampoos and conditioners generally contain high levels of conditioners to the point that a separate conditioner may not be required.


Most shampoos contain ingredients other than detergents and moisturizers. Shampoos contain fragrance to cover the chemical smell of shampoo, and many contain coloring to make the product more attractive. Shampoos also contain preservatives, which extend the shelf life of the product by preventing the growth of bacteria and other microbes. Additionally, the shampoo has a number of ingredients used to thicken the shampoo so it is easier to use, and ingredients to bind together the components of the shampoo to keep the ingredients from separating in the bottle. Finally, shampoos have ingredients that keep the shampoo slightly acidic, so it is pH-balanced to be healthy for your hair.

Specialized shampoos may contain small amounts of color that can be deposited onto the hair. Alternatively, medication may be added to specific shampoos, such as those for treating dandruff or head lice.

About this Author

Louise Tremblay recently finished an M.Sc. in molecular and cellular biology in Ontario, Canada, and is new to freelance writing. She has experience writing articles and Web content on science, heath and fitness, diet and personal wellness.