How Shampoo Works

Shampoos are formulated with cleansing agents called surfactants (a type of detergent), which are small molecules that have "water-attracting heads" and "oil-attracting tails".

When you mix shampoo with water and apply it to your hair, lather is formed. This happens when the water-attracting molecules in the shampoo are drawn towards the water, and the oil-attracting molecules are drawn towards the oil and grease on the scalp (as well as other dirt and skin particles in the hair).

The lathering action creates a push-and-pull effect on the oil and grease, essentially lifting it from the hair. Shampoo cleanses by stripping sebum (oil secreted from hair follicles) from the hair. While sebum is a necessary element of the hair because it provides a protective barrier on each individual strand, it also attracts and collects flakes, styling products, and dirt (especially around the hairline). When shampoo removes sebum, it also removes all of the unwanted residues from the hair.

*While shampoos and soaps both contain surfactants, you should avoid using soap to wash your hair. The surfactants found in soap bind and remove oils too much, making it harmful to your hair. Shampoo uses a different class of surfactants, which are balanced in order to remove just the right amount of oil from the hair.