The acid mantle protects the skin from dehydration, as well as from micro and noxious organisms through a hydrolipid film formed from sebaceous and sweat glands with a pH of about 4.5. It is also known under the term oily film, although less protective function is attributed to the eponymous acid there than under the concept of acid mantle.
What is the protective acid mantle?
The acid mantle protects the skin from dehydration through a hydrolipidic film formed from sebaceous and sweat glands with a pH of approximately 4.5. In medicine, the definition of the term acid mantle is controversial because a large number of pathogenic bacteria also feel comfortable in an acidic environment and can multiply there. This concept is predominantly propagated by manufacturers of supposedly “pH-friendly” personal care products for product differentiation. The skin‘s protective mechanism produces sweat and grease throughout the day. Sweat contains organic acids and sebum contains fatty acids. These two “helpers” regulate the pH value in a range between 4 and 6. Since this protective function is distributed over the entire body like a mantle and is located in the acidic pH environment, the definition is self-explanatory. The medical specialties are dermatology and physiology.
Function and task
The skin is the largest and therefore most important human sensory organ. It protects our body and serves as a contact surface with our environment. Healthy skin has an effective protective acid mantle, which acts as a barrier to protect the human organism from the penetration of pathogens such as viruses, bacteria, fungi, allergens and chemical substances. The protective skin mantle ensures a balanced moisture balance and protects against external environmental influences such as heat, cold and injuries. The skin is a sensory organ that enables people to perceive sensory impressions such as heat, cold, pressure and pain through touch. The skin barrier in the form of the acid mantle is one of the most important components of the human skin and is closely linked to the cornea. It is similar to a wall structure in which several layers of corneal cells are held together by epidermal lipids (horn lipids). The denser this bond is, the more resistant the skin is. The protective skin mantle consists of a thin film of fat and water covering the horny layer. It is composed of parts of the horny cells as well as sweat and sebum. Due to perspiration, the environment of the acid mantle is slightly acidic. This condition is ideal for the balanced bacterial balance of a healthy skin flora. Unwanted and harmful foreign germs in the form of bacteria, viruses, fungi and other microorganisms cannot multiply and penetrate the body with an intact protective acid mantle. The acid mantle protects against alkaline substances and foreign germs. Without an acidic environment, the pH would rise to 9 or 10 and become an ideal breeding ground for foreign germs, as they feel very comfortable in an alkaline environment. However, physicians assume that the protective function of the acid mantle cannot be attributed exclusively to a low pH value, but is due to an interaction of several secretions secreted by the skin glands. The protective film of the skin produced by the sebaceous and sweat glands contains water as its main constituent. Other ingredients are uric acid, urea bactericidal peptides, electrolytes and fatty acids. This interaction forms an ideal synergy to prevent the growth and multiplication of non-resident microorganisms in the form of a chemical barrier. The fats secreted by the sebaceous glands are deposited in the horny layer of the skin, making it supple and water-repellent.
Diseases and ailments
When medicine talks about the pH of human skin, it means the thin layer of moisture on the skin, consisting of sebum and sweat, which forms the protective acid mantle with a pH between 4 and 6. This value indicates that the protective skin film has a slightly acidic environment in which a variety of beneficial bacteria feel comfortable. With the reduction or increase of perspiration on the skin, this value can change. This change depends on how a person eats, how much he or she exercises, whether the person plays sports or takes medication. Sweat formation is therefore involved to a large extent in the formation of this protective mechanism.The unpleasant odor associated with sweating is caused by the decomposition of skin bacteria. The pH value and thus the acid mantle react with changes in the short term when people cleanse their skin with soap or use cosmetics. These products have alkaline substances that help to remove the greasy sebaceous layer on the skin. After showering, the skin feels clean and fresh, but in reality part of the acid mantle has been removed in the form of the skin’s natural oils. This is also due to the fact that water registers a pH value of 7, and additionally attacks the acid mantle during showering. In addition, these cleansing products remove the natural skin flora in the form of beneficial lactic acid-producing bacteria, which are important for stabilizing the pH. Most manufacturers of cosmetics and skin care products like to advertise that their products are pH neutral or even help to restore this value. However, this statement is a marketing strategy of the advertising industry. These supposedly acidic or pH-neutral products contain surfactants that remove from the skin what is actually supposed to protect it: the sebaceous and oily film in the form of the protective acid mantle. This makes the skin more susceptible to the side effects of creams, soaps and other personal care products. If the acid mantle is sensitively disturbed and the pH value is out of balance, allergies, skin irritations, skin impurities, eczema, abscesses and inflammations can form on this basis. Although a healthy skin flora restores an out-of-balance pH value and a protective acid mantle within a few hours, care should still be taken in personal hygiene not to stress the skin by excessive cleaning. Hygiene would then be counterproductive.
