Non-oxidative Hair Dyeing

Non-oxidative hair dyeing processes are often referred to as direct dyeing, since the dyes are applied directly and the molecules remain... 

There are two main groups of hair-dye products according to the mechanism involved in producing the colour. One is based on a non-oxidation mechanism, whereas the other involves an oxidation mechanism. 

According to how long-lasting they are, hair-dye prodncts may be classified into three gronps temporary, semi-permanent, and permanent hair colonrs. The two formers are based into a non-oxidation mechanism, whereas the last is based mainly on oxidation reactions although other chemicals which impart progressive permanent hair colonr do not follow this mechanism. They are discnssed below. 

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