How does pH influence cuticle opening and closing during a color service?

• A. pH only affects scent of products.
• B. Higher pH opens cuticle for penetration; lower pH closes cuticle to seal color and set tone.
• C. Higher pH closes cuticle; lower pH opens cuticle to allow pigment penetration.
• D. pH has no effect on cuticle.

Answer: (B)

Understanding how pH affects the hair cuticle is essential in a color service. The cuticle is the outer protective layer of each strand, and its state determines how easily color molecules can enter the cortex. When a formula with a higher pH is used, the cuticle swells and lifts, creating gaps that allow pigment to penetrate for the desired lift and tone. After processing, switching to a lower pH helps the cuticle lie flat again, sealing the color inside and helping to set the tone and improve shine. So, alkaline environments open the cuticle for penetration, while acidic environments close it to lock in the color. This direct effect on the cuticle is why pH matters beyond anything like scent, and why an opposite or no-effect statement doesn’t fit.