Soap strips away the skin’s natural protective barrier. How does your skin feel when you use soap? Tight? Dry? Uncomfortable? This is because soap has an alkaline pH that strips away all the protective oils. It leaves your skin vulnerable – sensitised and dehydrated.
A cleanser should respect the skin’s natural acidic pH, which is between pH 4 – 6, so it does not strip the skins protective oils. This means less dehydration and reduced sensitivity.
Source: Dermalogica Uk