Getting grey hair in humans is a sign of aging. Hair colour is basically controlled by
melanin pigment produced within hair
follicles from which hair grow. A hair has two parts:
SHAFT and
ROOT.
Root is anchored in the
hair follicle under the scalp and it produces visible part of hair called
shaft. Melanin producing cells called melanocytes of hair
follicles produce
melanin that imparts
colour to shaft viz. dark, dark brown, blonde, red or anything in between these colours. Nature and intensity of hair shaft colour depends upon quantity of
melanin produced in hair follicles by melanin producing cells. For example, dark hairs have more melanin than red hairs while as white hairs have no melanin. Skin colour is also controlled by quantity of melanin produced in skin in humans. Hair grow grey, silver or white with advancing age because of death of melanin producing cells of hair follicles. Growing of grey hairs at early age in some people is genitically controlled, therefore, heriditary in origin. Therefore, the trait of having grey hairs at early age is acquired from parents by the offsprings. Common belief that big shock or trauma can turn a person''s hair grey overnight is as yet not supported by scientific findings. Is there any correlation between a trauma and a hair colour needs thorough investigation?