Exactly What IS a "COUPLER" in a Hair Coloring Product?

A coupler is generally an aromatic compound, either a benzene derivitive or a napthol. Couplers modify the color generated when used together with the primary intermediates and the oxidation ingredient (peroxide). Couplers are commonly classified into three

groups: Yellow-green, Red, or Blue.

Couplers "couple"("bond) with the products primary intermediates, which form the shade a

color product will produce, AND the couplers help bond these primary intermediates to the action

of the oxidative ingredient... peroxide. So, three things help a hair color product 'stick together" and create a new shade in the hair.

1. Primary Intermediates

2. Coupler

3. Oxidative ingredient