Hair coloring by lay people may not be sufficiently accurate. Hair that has been damaged by excessive exposure to chemicals is considered "over-processed". This results in dry, rough and fragile hair. In extreme cases, the hair can be so damaged that it breaks off entirely. The main cases of hair breakage are: Lack of moisture and oils, poor diet, stress, over processing or illness. Skin and fingernails are made of a similar type of keratinized protein as hair. That means that drips, slips and extra hair tint around the hairline can result in patches of discolored skin. This is more common with
Human hair color can be found spread around most of Europe. Studies in 2012 showed that naturally blond hair of Melanesians is caused by a recessive mutation in tyrosinase-related protein 1 (TYRP1). In the Solomon Islands, 26% of the population carry the gene; however, it is absent outside of Oceania. Black hair is the darkest hair color. It has large amounts of eumelanin and is more dense than other hair colors. Auburn hair ranges along a spectrum of light to dark red-brown shades. The chemicals which cause auburn hair are eumelanin (brown) and pheomelanin (red), with a higher proportion of red-causing pheomelanin than