You should avoid soap on your face because it is a harsh surfactant which indiscriminately removes good lipids as well as dirt and sebum. This causes the breakdown of the skin's natural moisture barrier which results in water passing out of the skin more rapidly making it severely dry.
Further, it lets materials into the skin such as irritants, allergens, and unfriendly micro-organisms which can provoke inflammation and the ultimate breakdown of key structural proteins and water-binding carbohydrates like hyaluronic acid.
Soap is also very alkaline (increases the pH of the skin). This produces a surface that is hostile to the micro-organisms that are needed to maintain the skin's immune system.
By Ewelina Baranska