Which statement about the natural pH range of hair and skin is true?

• A. It is alkaline, around pH 9.
• B. It is acidic, about pH 3.
• C. It is neutral, around pH 7.
• D. It ranges from 4.5 to 5.5.

Answer: (D)

Natural hair and skin stay in a slightly acidic range to form a protective acid mantle. This environment, about 4.5 to 5.5 on the pH scale, helps keep the skin barrier intact and the hair cuticle smooth, while supporting enzyme activity and moisture retention. An alkaline pH around 9 would lift the cuticle and dry the hair and skin, making them more prone to damage. A very acidic level around pH 3 is too harsh for most people and can irritate the skin. A neutral pH around 7 doesn’t provide the same protective benefits as the slightly acidic range. Therefore, the statement that the natural pH range is about 4.5 to 5.5 is true.