Why does hair go grey

A. Grey hair is caused by the loss of melanin, the pigment in our hair that gives it colour, over time. Melanin is produced by cells called melanocytes. Melanocytes eventually die and so stop producing melanin. As a result the concentration of melanin in your hair shaft decreases and you end up with grey hair. Once the melanin disappears completely the hair is white.

Exactly how hair loses its pigment remains unclear. Genes have a large role in the production of melanin, some families are characterised by grey hair in their twenties, some families have hardly any members with grey hair whatever their age.

Q. If hair is dead, where does hair colour come from

A. The melanocytes pass melanin to adjoining cells called keratinocytes, which produce the protein keratin: hair's chief component. When the keratinocytes undergo their scheduled death, they retain the melanin, giving us our hair colour.

What colour hair you have is determined by the type of melanin you have, there are two types: eumelanin, which is dark brown or black, and pheomelanin, which is reddish yellow.

Q. How do hair colour restorers work

A. Some people are unhappy about their grey hair and there are lots of products available that promise to restore natural hair colour.

Generally hair colour restoreses work by introducing a pigment that mimics melanin. The more you use the product the darker your hair becomes.

Q. What happens if I pluck grey hairs out

A. Once the cells responsible for producing melanin, the melanocytes, are dead the hair follicle can only produce grey hair. So plucking out grey hairs will only result in another one growing in its place.

Do you want to know why the human body behaves the way it does Click here to ask.

by Lisa Cardy