pH
Tells how acidic or alkaline a chemical is on a scale of 1-14; 0-6 is acidic, 7 is neutral, and 8-14 is alkaline. The skin’s pH should be around 4.5-5.5, which is considered acidic. Raising or lowering the skin’s pH too much can result in dryness, irritation, acne, excessive oiliness, or hyperpigmentation.