Does a shampoo cap really lighten hair?
On One Hand: Virgin HairA shampoo cap will lighten virgin hair. Virgin hair has never been colored or lightened. Developer used in a shampoo cap penetrates the hair cortex and lightens the hair’s natural color by replacing the natural color molecules with the color molecules in the hair dye.The amount the hair is lightened will depend on the strength of the developer used in the shampoo cap. Generally, a shade or two of lightening will occur in virgin hair.On the Other: Color-Treated HairA shampoo cap will not lighten hair that already has been color-treated. Once natural color molecules are replaced by the color molecules in hair dye, they cannot be affected by a shampoo cap. The molecules in the cortex of color-treated hair remain there until lightened by bleach and developer.Bottom LineWhile a shampoo cap may lighten virgin hair to a small extent, a shampoo cap is used mainly for toning pre-lightened hair to a desired shade of color. It will not lighten hair that has already been co
