Acidic film on the skin that determines the skin’s pH of 4.5-5.5, as well as protects the stratum corneum from damaging environmental factors and harmful bacteria. Made of oils, fatty acids, lactic acid, amino acids, and water. When stripped, skin feels tight and dry and is more prone to acne.
Ingredients that are skin lighteners, sunscreens, anti-aging, or anti-acne FDA regulated because of their potential to irritate the skin Usually in low percentages to prevent irritation AHAs, BHAs, retinol, sulfur, hydroquinone, oxibenzone, vitamin C, and kojic acid are a few examples
Alpha hydroxy acids, or AHA’s, are chemical exfoliants. The most commonly known are lactic and glycolic acid. Mandelic acid, citrus acid, malic acid, and tartaric acid are other alpha hydroxy acids. They can be used in peels or daily exfoliants, depending on the percentage they are used at.