What should be the pH level of a shampoo for the scalp?

A neutral pH level, which is approximately 7, is ideal for a shampoo designed for the scalp. The scalp's natural pH typically ranges from 4.5 to 5.5, making it slightly acidic. However, shampoos formulated with a neutral pH can help in maintaining the overall balance of the scalp environment without causing irritation or disrupting the scalp's natural barrier.

Using a shampoo that is too acidic can strip away natural oils, leading to dryness and irritation. Conversely, a shampoo that is alkaline or highly alkaline can disrupt the scalp's pH balance, potentially resulting in overproduction of oil or irritations and conditions like dandruff. Therefore, a neutral pH is the most beneficial for maintaining scalp health while effectively cleansing the hair without causing harm.