What is the normal pH of the skin?

The normal pH of the skin is slightly acidic, typically ranging from about 4.5 to 5.5. This slightly acidic environment plays a crucial role in maintaining the skin's barrier function, as it helps to inhibit the growth of harmful bacteria and pathogens, which thrive in more neutral or alkaline conditions. The acidity of the skin is largely due to the presence of natural moisturizing factors and the secretion of sebum, which contains fatty acids that contribute to this pH level. This acidic mantle is essential for skin health, as it supports the skin microbiome and enhances the skin's overall resilience against external irritants and infections. Understanding this aspect of skin physiology is vital for effective skincare and the formulation of products that respect and maintain this natural pH balance.