Let’s Get Geeky – Permanent Haircolor

Monday, July 23, 2012
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Haircoloring products generally fall into four categories: temporary, semi-permanent, demi-permanent and permanent. Today I will explain the chemical action of permanent haircolor, which, along with demi-permanent formulas, is most widely used in salons.

Permanent haircolor is most often used when 1) covering grey hair and/or 2) a shade lighter than the natural shade is desired. They typically contain an alkalizing ingredient (usually ammonia), and oxidizing ingredient (usually peroxide), and tints.

The alkalizing ingredient opens the cuticle of the hair shaft to allow tint molecules to enter the cortex. It also aids in the development of tints in the cortex and in the lightening action.

The oxidizing ingredient creates oxygen, which is essential to both lightening and developing color molecules. Lightening occurs when an alkalizing agent is added to peroxide or oxidizing agent. The peroxide becomes alkaline and is able to penetrate the cortex and break up the melanin located in the cuticle. The higher the volume, or concentration, of peroxide, the more lightening you will experience.

Permanent tints begin very small, in fact they are initially dye precursors. Once they enter the cuticle, they expand with the aid of hydrogen peroxide into larger tint molecules. These molecules are then trapped in the hair shaft and can not be shampooed out. This is what makes permanent haircolor permanent.

To recap, permanent haircolor opens the outer layer of your hair strand to allow small dye particles to enter the inner layer. Once inside, the tints oxidize to create larger molecules that remain in the hair's core. They can simutaneously lift natural haircolor and deposit artificial haircolor, making it a snap to go a bit lighter or cover grey.

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3 Responses

  1. If the permanent color is trapped in the hair shaft, what is the function of special shampoo for color-treated hair? Also, I recently read that it’s a good idea to change up your color-treated-hair shampoo regularly. Is this true? And if so, how often?

  2. Great question! Shampoos for color treated hair are formulated to be extra gentle. As you may recall from my “Let’s Get Geeky” post on pH (http://parlordiary.com/2011/09/17/geeky-ph/), even water has an alkalizing effect on hair which can slightly raise the cuticle. Raise the cuticle enough and throw in heavy duty surfactants and some of those tint molecules will slip out of the cuticle. Color-safe shampoos contain surfactants that remove dirt and oils without stripping.

    Color protecting shampoos and conditioners usually also contain UV filters, since sun exposure also causes fading of permanent dyes. This is due to the natural bleaching action of the sun. The rays break up your natural melanin as well as tint molecules.

  3. Also, I don’t think it’s necessary to change shampoos. I think that is an urban myth. I do, however, recommend periodically using a clarifying shampoo. They are great for removing product buildup and mineral deposits from hard water. Clarifying shampoos WILL remove color so be sure to wait until just before your color appointment.

  4. […] Permanent haircolor typically requires an alkalizing ingredient, an oxidizing ingredient, and pigments. The most common alkalizing ingredient is ammonia, which increases hair’s porosity, making it more prone to frizz and color fading. It also gives haircolor an awful smell and can be very irritating to skin, eyes, throat, and lungs. I’ve had plenty of coughing fits after accidentally inhaling color fumes. Most hair dyes (even semi- and demi-permanent formulas) also include PPDs (para-phenylenediamine), which can trigger allergic reactions and lead to dermatitis. In fact, they are the primary reason why allergy patch tests are so highly recommended. […]

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