pH stands for "potential hydrogen" and is used to describe the acid-alkaline ratio of a substance, which ranges from 0 (the most acidic) to 14 (the most alkaline). The skin's barrier, which is known as the acid mantle, is responsible for keeping in lipids and moisture while blocking germs, pollution, toxins, and bacteria. To work its best, the acid mantle should be slightly acidic, at a 5.5 pH balance.
When your skin is too too alkaline, it becomes dry and sensitive. Although it’s rare for skin to be overly acidic, the result is often red, inflamed skin and breakouts.