Shampoo is a detergent, not a soap. Detergents and soaps have different properties. Soaps lose effectiveness and produce soap scum in hard water. Detergents don

Shampoo is a detergent, not a soap. Detergents and soaps have different properties. Soaps lose effectiveness and produce soap scum in hard water. Detergents don't. Many body cleansers also cause less skin irritation than your common soaps do because they control alkalinity and add moisturizers.