Why don't eyebrows grow past a certain point?

hair goes through 3 stages of growth:

anagen, catagen, and telogen.

anagen is the "growth stage" when hair grows. the cells in the root of the hair are dividing rapidly. a new hair is formed and pushes the club hair up the follicle and eventually out. during this phase the hair grows about 1 cm every 28 days. scalp hair stays in this active phase of growth for 2-6 years. some people have difficulty growing their hair beyond a certain length because they have a short active phase of growth. on the other hand, people with very long hair have a long active phase of growth. the hair on the arms, legs, eyelashes, and eyebrows have a very short active growth phase of about 30-45 days explaining why they are so much shorter than scalp hair.

catagen is the "transition phase" where, at any time, 3% of all hairs are in this phase. this phase lasts for about 2-3 weeks. during this time growth stops and the outer root sheath shrinks and attaches to the root of the hair. this is the formation of what is known as a club hair.

telogen is the final "resting phase" and accounts for 10-15% of all hairs. this phase lasts for about 100 days for hairs on the scalp and much longer for hairs on the eyebrow, eyelash, arm and leg. during this phase the hair follicle is completely at rest and the club hair is completely formed. pulling out a hair in this phase will reveal a solid, hard, dry, white material at the root. about 25-100 telogen hairs are shed normally each day.

hope this makes sense to ya!

In the DNA/RNA code of the hair for eyebrows they have a short life span... about 6 months. Essentially they keep dying, falling out and being replaced with new ones. Mine get hecka-long, though, and I have to trim them every so often. This happens when you get older, as the DNA/RNA code breaks down and they mutate.

The skin is very thin in this area..(have you ever been cut? you bleed like a stuck pig!) You will get a few hairs that get longer...ever see an elderly man's eyebrows? For the most part they won't grow unless you shave! that stimulates the hair folicale...like on your legs! and underarms...this is why ALL hair on your body doesn't grow, or you'd look like a Yeti! (abominable snowman)

Genetics and DNA-Like the hair on your arms and legs, human gentics will not allow it to grow any further than a ceratin way, the hair will fall out once it gets too long. The human body is a wonderful thing. try wikipedia or google for more info!

cause they know what would happen to em if they grew to long...

but I think it is because they grow from the top (as opposed to the root), and they taper off at the end, so once they've grown to a certain point they cant grow anymore.

The body is smart and needs the other calcium to strengthen your bones. It is like the brain separates what part of the body needs how much of what while keeping another part just as strong and keep you healthy

You should take a look at Andy Rooney if you think that. That guy has caterpillars with 18-inch long hair over his eyes. :)

Would you cut your eyebrow hair like that if it grew like the hair on your head??? And who in the hell have time to shave their eyebrows like that...just be glad you dont have bushy eyebrows like that...and a friend like me b/c i would call you push broom. ROFLMFAO.

All hair on your body is renewed every seven years.

You should see my grandpa's there 2 inches long!!!!