What is the pH of temporary hair color?

• A. 7.0 - 8.0
• B. 4.0 - 5.0
• C. 9.0 - 11.0
• D. 12.0 - 13.0

Answer: (C)

pH indicates how acidic or basic a product is, and hair color formulations are built to work with the hair’s structure at different pH levels. Temporary hair color is meant to sit on the outer surface of the hair and wash out with shampoo, rather than penetrate deeply. An alkaline environment helps the hair cuticle lift slightly and creates a surface where pigment molecules can adhere more readily, which is exactly what you want for deposition on the surface.

That’s why temporary color is formulated in the alkaline range around 9 to 11. A pH in the acidic range (4–5) would keep the cuticle tight and hinder surface deposition, while pH values well above 11 can be too harsh and unnecessary for this purpose. A near-neutral or mildly alkaline range (7–8) could work for some products, but the strongest, reliable surface deposition for temporary color comes from the higher alkaline range of 9–11.