North Dakota Cosmetology Practice Exam

The pH range of neutral shampoo is typically considered to be between 4.5 to 7. This range indicates that the shampoo is neither too acidic nor too alkaline, making it suitable for a wide variety of hair types and conditions. A pH closer to 7 is gentle on the scalp and hair, helping to maintain the natural pH balance. The skin and hair are slightly acidic, with a natural pH around 4.5 to 5.5, which helps to protect the hair cuticle and skin barrier. Therefore, a neutral shampoo within this pH range aids in cleansing without stripping away essential moisture or causing irritation. In comparison, a pH of 0 to 3 is extremely acidic, which can be harsh on both hair and scalp. A pH range of 3.5 to 5.5 leans toward the acidic side, which can be beneficial for certain hair types but is not classified as neutral. Finally, a pH of 7.5 to 10 would be considered alkaline, which can lead to dryness and damage by lifting the hair cuticle too much. Thus, the indicated pH range for neutral shampoo is effectively balanced for safe and gentle cleansing.