Hair Dye

Hair coloring is used for a variety of purposes; most commonly to return gray hair to its previous color, to change hair color to a shade regarded as more desirable, or to return hair to its original color after chemicals (e.g. tints, relaxers, sun bleaching) have discolored it. Hair coloring products are typically categorized based on the length of time they effect the colored hair. The four most common classifications are 'temporary', 'semi-permanent', 'demi-permanent' (sometimes called 'deposit only) and permanent.

Temporary hair color is available in various product forms including rinses, shampoos, gels, sprays, foams and others. This type of hair color is typically used to give brighter, more vibrant shades or colors such as orange or red, that may be difficult to achieve with semi-permanent and permanent hair color. Temporary color is also used by some teens for events at school and Halloween. This phenomenon is because temporary hair colorants do not penetrate the hair shaft itself. Instead, these color particles remain adsorbed (closely adherent) to the hair shaft and can be easily removed with a single shampooing. However, even temporary hair coloring agents can persist if the user's hair is excessively dry or damaged, conditions that allow for migration of the pigments from the exterior to the interior of the hair shaft. While temporary hair color products hold a lesser market than semi-permanent and permanent agents, they have value in that they can be easily and quickly removed without bleaching or application of a different coloring product.

"Hair lightening," referred to as "bleaching" or "decolorizing," is a chemical process involving the diffusion of the natural color pigment or artificial color from the hair plus the raising of the cuticle making the hair more porous. This process is central to both permanent hair color and hair lighteners. Most hair lighteners and bleaches can make your hair turn gray at a younger age.

Hair coloring involves the use of chemicals capable of removing, replacing and/or covering up pigments naturally found inside the hair shaft. Use of these chemicals can result in a range of adverse effects, including temporary skin irritation and allergy, hair breakage, skin discoloration and unexpected hair color results. Additionally, there is ongoing debate regarding more serious health consequences of hair color usage, including lead poisoning.