Human skin has an outer, protective layer called the acid mantle. This skin barrier is a thin, acidic film that keeps bacteria out of the skin cells. If the mantle is temporarily removed by harsh soaps or sun damage, the skin becomes susceptible to rashes, breakouts, and infection.
This acidic film is created when the human body combines sweat and sebum, or skin oil. The skin naturally secretes these substances, and the acidity of the mantle is measured by its pH, which is measured on a scale of 1 to 14. Healthy skin usually has a pH between 4.2 and 5.6. Skin pH can vary in different parts of the body, and men generally have a slightly higher pH than women. Substances with a pH of below 7 are acids.
The acid mantle protects the skin by killing bacteria before it can get inside the body. It also helps the skin maintain moisture and combat dehydration.
Strong alkaline soaps, which have a high pH, and excess sweating can destroy the mantle or alter its pH. If the acid mantle is stripped off the skin, bacteria can attack and infection may occur. The removal of this layer also disturbs the dead skin cells found in the top layer of skin, called the epidermis.
While too many dead skin cells on the skin’s surface can dull its appearance, a small amount of these cells play a positive role. Dead cells help keep bacteria away from healthy skin cells. If the mantle is destroyed, it will usually be replenished naturally over time, usually within two or three weeks.
Prolonged skin issues, such as acne, may be caused by an alkaline skin pH or unstable acid mantle. When the skin’s pH is no longer acidic, bacteria can constantly cause pimples. People prone to acne may want to wash with strong soaps, which can make pH levels worse, but acne treatments that focus on restoring the skin’s pH to acidic levels can help alleviate breakouts.
Skin creams are available to create a chemical protective barrier if needed. AcidMantle® is the brand name of a skin cream used primarily to treat skin irritations like diaper rash. People can help maintain a healthy acid mantle by avoiding harsh soaps and using sunscreen. Applying a daily acidic moisturizer can also help, as can using pH-balanced skin care products.