When we're talking about hair loss, the word 'follicle' comes up a lot. Follicular damage, shrinking follicles, follicular unit transplants... But do you really know what a hair follicle is, and how it can affect hair growth and loss?
A hair follicle is a tube-like organism that extends from the epidermis (the outer layer of the skin) to the dermis (the deeper layer of the skin). The follicle is built up of several layers, each of which has a different purpose.
The very bottom part of the follicle is the bulb, which contains the living part of the hair. Within this is something called the papilla, which contains the blood vessels that help to nourish and renew the cells of the hair. These cells divide faster than any other cells in the body – around every 20 –70 hours.
There are two sheaths that grow around the follicle. The inner sheath follows the hair shaft up to just below the opening of the sebaceous gland, while the outer sheath continues all the way up to the gland. These sheaths protect the growing hair shaft.
How do hair follicles get damaged?
There are a number of different ways in which a hair follicle can get damaged: if hair is pulled too tight consistently, through aggressive hair styling (rarely), or more commonly due to a weave or other type of hair extension, this can cause damage to the follicle and result in hair loss.
In men, male-pattern baldness is thought to be caused by the hormone dihydrotestosterone, which causes follicles to shrink. There are a number of medications available to counter this, although they tend to have some nasty side effects.
What other hair loss treatments affect the follicles?
All hair loss and hair restoration treatments affect the follicles in some way – if they didn't, then they wouldn't work!
One major hair loss treatment to do with the follicles, though, is hair transplant surgery, where hair follicles are actually transplanted from one area of the head to another. This is usually performed on men with male-pattern baldness, who tend to have living hair follicles at the back of the head, which are commonly transplanted to the hairline, where follicles have shrunk so much that they can no longer produce hair.
So next time you're looking at a hair loss product, read the back of the bottle and see what effect it claims to have on the hair follicles. If the word “follicle” isn't mentioned, you're probably wasting your money.