We all know that hairs grow from epidermal layer. It is made up of highly fibrous and insoluble protein which is known as keratin. This protein is found in hairs as well as in the skin. This keratin is produced from a zone which is present in outer most layer of the skin. This outer most layer is known as keratinisation zone. It helps to provide water to the skin.
This keratin is pigmented and it is highly pigmented in hair. The black colour of our hair is because of this pigment which is present in large concentration in epidermis layer. The black colour is also due to the presence of pigment in keratinocytes. Melanocytes are a pigment which gives keratin its pigment colour. These melanocytes are situated in the inner layer. These melanocytes undergo a long process and then get secreted. After getting secreted these melanocytes gets engulfed with keratinocytes which helps in making epidermal cells.
Melanin is a type of protein which later gets converted into dihydroxyl phenyl alanine which is a type of oxidation enzyme. After this series of reaction takes place and finally they get formed in melanoprotein. Hair growth takes place from the germinal matrix of hair follicle. Germinal matrix is found in the proximal enlargement and is called hair bulb. All these are made up of cornified cells.
So, white hairs may develop because of absence of melanin pigments. This absence of melanin pigment may be due to absence of one or more enzymes which lead to failure of melanin.