:how do hairs know when to stop growing


They are just dead, right. Or are they?

the hairs on some areas will stop growing after about 2 inches. And as soon as I cut them off, they will grow again to 2 inches and stop. How?

In: 3

They don’t. There’s wear and tear on them and any section of hair will survive X amount of time. It grows out more or less constantly and once it’s too old and worn, that section will break off leaving your hair that long. Different hairs, like arm hair or head hair, will have different strength, durability, and growth rate. But both will behave the same: Grow at a constant rate and the damaged ends break off.

With the exception of a rare genetic mutation that causes one’s hair to grow indefinitely, all the hair follicle has a set amount of time before it essentially pops out the hair and starts to grow a new one. The hair on your head and the hair on your arms or in any facial hair all have different time limits and/or growing speeds. These dead hairs fall of you during the day as you move and do stuff or when you wash your hair. You just have so many hairs, you just don’t notice the new ones growing in