What is the function of the acid mantle on the skin?

The acid mantle serves an essential role in protecting the skin's barrier. This thin film of fatty acids and lactic acid sits on the surface of the skin and helps to maintain a slightly acidic pH, typically between 4.5 and 5.5. This acidity is critical for creating an inhospitable environment for harmful bacteria and pathogens, while also supporting the growth of beneficial microorganisms that contribute to skin health.

By maintaining this protective barrier, the acid mantle helps to prevent irritants and allergens from penetrating the skin, thereby reducing the risk of infections and skin conditions such as eczema and dermatitis. Furthermore, a healthy acid mantle supports the skin's overall hydration by limiting transepidermal water loss, but its primary role remains as a protective barrier.

In contrast, while enhancing skin color, preventing moisture loss, and regulating body temperature are important functions of skin and other skin systems, these do not pertain specifically to the core function of the acid mantle.