Q: Which way does hair grow? Does it grow from the scalp or from the end of the hair strand? I think that hair grows from the scalp, but my friends claim that it are the ends of the hair strands that gain length.
A: Congratulations. You are the correct one in your peer group. The hair that we see emerging from the scalp is death tissue – specifically strands of protein chains that have hardened and are covered by a sheath of
overlapping scales – also made of proteins.
(Click to enlarge)
The only living part of the hair is the follicle inside the skin of the scalp and the point at which the hair connects to the follicle is the papilla, which produces hair cells.
Therefore the living cells form in the papilla and as new cells are formed, the cells begin to be pushed up and out the follicle, during which time they keratinize and become the hair shaft we know and love.
And as an added tidbit that many people may not know. The cells of the hair that are formed in the papilla divide faster than any other cells in the human body – often doubling in
number in 24-72 hours. This is the reason for the rapid rate of growth of the hair as opposed to other bodily tissues.