What pH level is recommended for shampoo used on lightened hair?

The recommended pH level for shampoo used on lightened hair is between 4.5 and 5.5. This pH range is ideal for maintaining the hair's natural acidity, which is important for preserving the integrity and health of lightened hair. When hair is lightened, it undergoes chemical changes that often lead to an increase in porosity and susceptibility to damage. A shampoo with a pH in this range helps to keep the cuticle layer of the hair smooth, which can minimize damage and enhance shine.

In addition, shampoos formulated with a pH that is slightly acidic (around 4.5 to 5.5) also work to close the hair cuticle after the cleansing process, reducing frizz and protecting the hair from environmental stressors. This pH balance is crucial for maintaining the vibrancy and longevity of color-treated hair while ensuring it remains manageable and healthy.

Using shampoo with a pH outside this recommended range may disrupt the hair's natural balance, potentially leading to dryness, brittleness, or color fading. Therefore, choosing a shampoo within the specified pH range is vital for anyone with lightened or chemically treated hair.