How Does Hair Grow?
Hair grows out of tiny openings (or follicles) in the skin. Each hair is a series of scaly cells piled one on top of the other. These hair scales are made out of a tough substance called keratin. At the base of each hair is a bulb-shaped root. This root receives nourishment from the body and produces keratin.
As new hair cells form, they push the old scales up through the follicles, causing the hair to grow and lengthen. Hair color is due to a coloring matter known as pigment. This pigment becomes part of the hair cells as they form in the roots.
The hair is dead by the time it is long enough to poke out through the skin. Yes, hair is dead. That’s why it doesn’t hurt to get a haircut. Hair on the rest of your body goes through this same process, but the whole cycle only lasts for a month or so. That’s why body hair does not grow very long in length like the hair on your head does.
Here are some facts about follicles and your hair:
- You are born with all of the follicles you will ever have — about 5 million.
- You have about 100,000 follicles on your scalp, which is the skin on your head.
- Hair grows very fast and male hair grows faster than female hair. The only part of your body that grows faster is bone marrow, the soft stuff inside your bones. The hair on your head grows about 6 inches a year. So, even though it’s one of the fastest-growing things on your body, it takes a while to grow it really long.
- You lose about 50 to 100 hairs a day. That’s because the follicles don’t all grow hair at the same time. Each scalp follicle grows hair for a few years and then takes a break. When a follicle is on a break, the hair in the follicle falls out. Because the follicles take breaks at different times and the other hairs keep growing, you probably don’t notice when you lose hairs.
- Some follicles stop growing hair as you get older. This happens more in some people than in others. That’s why some people get thinner hair when they get older, or go bald.