Hair Dye

Hair dye is what you can use to change the color of your hair. It is very popular with many people, over 75% of american women use hair dye. Hair dye was traditionally applied to hair for one overall color whereas nowadays several colors are used to produce streaks or gradations in the hair.

There are three main types of hair dye; permanent, semi - permanent and temporary.

Semi - Permanent; It has smaller molecules than temporary dyes. The color will last repeated washing, normally 4–5 shampoos. Semi-permanents have very low levels of  peroxide and ammonia so they're much safer for damaged  hair. However, some dyes may still contain the carcinogenic compound p-phenylenediamine. 

Temporary; Is available in many forms such as shampoos, gels, and foams. Temporary hair dye is brighter than semi-permanent and permanent hair dye. It is often used to die hair for special occasions.The pigment molecules in temporary hair color are large so they can't penetrate the hairs cuticle layer. The color particles remain adsorbed in the hair and are easily removed with a single shampoo wash.

Permanent; A popular way to acheive permanent coloured hair is by using oxidation dyes. The ingredients of these products include 1,4-diaminobenzene or 2,5-diaminotoluene  a coupling agent, and an oxidant. 

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