Q. Dr. Said, I have another question for you. Most manufacturers recommend to process hair color at room temperature. But there are others who teach to process under heat. What is your opinion on this? Does heat give better color? Donna, Sweeny, TX
A. Donna, it is always recommended to follow the manufacturer’s instructions because each color line is designed to work under a specific set of conditions. Heat no doubt speeds up color development and dye diffusion into the hair and you may be able to reduce the processing time in half. Here is the big “BUT”: Heat also can act in opposite ways; First it enhances the diffusion of the dye molecules into the hair fiber, which is a desirable effect. Second, it speeds up the oxidation of the dyes in the dye mixture at or near the surface of the hair which may result in less dyes being available to go inside the hair, and in blocking the pores and hindering further diffusion of additional dyes. Remember once dyes are oxidized they cannot move into or out of the hair. This undesirable effect is much more intensified if the hair is contaminated with metals. So to avoid this negative effect and make heat work for you, you have to make sure the hair is free of metals before you apply color. A good chelating treatment such as our Get Pure hair clarifying treatment would help in this regard.