pH measures acidity in liquids on a scale that ranges from 0 to 14. It is often measured by an electronic device called the pH meter or with litmus paper. Your skin pH level is determined by the hydro-lipid layer, which helps control the ecosystem in which the bacteria and oils thrive on your skin. When the pH level is too high or too low, it disrupts your skin’s natural composition, which can lead to breakouts and redness. In fact, it can even increase the production of fine lines and age your skin.
The ideal pH level for skin is 5.5, but it can vary depending on your skin type. For oily skin, the pH is between 4 and 5.2, while it ranges from 5.2 to 5.7 for normal skin, and 5.7 to 7 for dry skin. Therefore, cosmetic products are produced with a specific pH level in mind to resolve or control specific concerns.
This scale will give you a better visual understanding of pH: