What is the ideal pH range for shampoo?

The ideal pH range for shampoo is 4.5 to 5.5 because this range is aligned with the natural pH of the scalp and hair. Hair and scalp have a natural acidic layer known as the acid mantle, which helps protect against environmental damage and keeps hair cuticles smooth. Using a shampoo within this pH range helps maintain the integrity of this protective barrier, ensuring that the hair remains healthy and less prone to issues like dryness or irritation.

Formulations that fall outside of this range could disrupt the balance of the scalp, leading to potential issues such as increased oiliness, dryness, or sensitivity, which can affect hair health. Therefore, the pH level in shampoos must be carefully considered to provide effective cleansing without causing harm. This is why shampoos designed for regular use typically aim for this optimal 4.5 to 5.5 pH level.