South Carolina Cosmetology Practice Exam

The optimal pH level for shampoo is between 4.5 and 5.5 because this range closely matches the natural pH of the scalp and hair, which typically ranges from 4.5 to 5.5. Maintaining this pH level helps to preserve the hair’s cuticle layer, ensuring it remains smooth and healthy while preventing excessive swelling and damage.

A shampoo within this pH range effectively cleanses the hair without stripping away natural oils or disrupting the scalp's acid mantle, which is important for preventing issues such as dryness and irritation. Additionally, shampoos formulated with this optimal pH can help to enhance color retention in color-treated hair and improve overall hair manageability and shine.

Understanding the importance of pH in hair care products is essential for cosmetologists, as it ensures that clients receive the best possible treatments while maintaining the integrity of their hair and scalp health.