What is true of the pH of human skin?

• A. It is acidic.
• B. It is neutral.
• C. It is alkaline.
• D. It varies widely.

Answer: (A)

Healthy skin maintains its surface in a mildly acidic state. The pH is typically around 4.5 to 5.5, shaped by secretions like sebum and sweat along with organic acids that create an acid mantle. This acidity helps preserve the skin’s barrier and provides antimicrobial protection, making the acidic environment beneficial. Neutral or alkaline conditions would weaken the barrier and promote irritation or microbial growth, respectively. While pH can shift somewhat with products, water exposure, or skin conditions, the normal state for healthy skin is acidic rather than neutral or alkaline, and it is not accurately described as varying widely.