# How Does Body Hair Know When To Stop Growing?

**URL:** <https://boards.straightdope.com/t/how-does-body-hair-know-when-to-stop-growing/460859>\
**Category:** Factual Questions\
**Created:** [August 21, 2008, 10:22pm UTC](https://boards.straightdope.com/t/how-does-body-hair-know-when-to-stop-growing/460859 "2008-08-21T22:22:43Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Huerta88](https://avatars.discourse-cdn.com/v4/letter/h/82dd89/32.png) [@Huerta88](https://boards.straightdope.com/u/Huerta88)\
**Post date:** [August 21, 2008, 10:22pm UTC](https://boards.straightdope.com/t/how-does-body-hair-know-when-to-stop-growing/460859/1 "2008-08-21T22:22:43Z")

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See title. The hair on your head (or your beard, if you have one) will just keep growing.

Not so armpit, chest, etc.

Or do they just fall out very very rapidly?

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**Author:** ![3waygeek](https://avatars.discourse-cdn.com/v4/letter/3/e95f7d/32.png) [@3waygeek](https://boards.straightdope.com/u/3waygeek)\
**Post date:** [August 21, 2008, 10:26pm UTC](https://boards.straightdope.com/t/how-does-body-hair-know-when-to-stop-growing/460859/2 "2008-08-21T22:26:58Z")

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[The Master speaks](http://www.straightdope.com/classics/a3_044a.html).

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**Author:** ![garygnu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garygnu/32/2924_2.png) [@garygnu](https://boards.straightdope.com/u/garygnu)\
**Post date:** [August 21, 2008, 10:28pm UTC](https://boards.straightdope.com/t/how-does-body-hair-know-when-to-stop-growing/460859/3 "2008-08-21T22:28:55Z")

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[Cecil](http://www.straightdope.com/classics/a1_097b.html) covered this one: Body hair follicles alternate between active, dormant, a new hair growth cycles. Each follicle has its own clock so it’s not all happening at once.

so

slow

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**Author:** ![Huerta88](https://avatars.discourse-cdn.com/v4/letter/h/82dd89/32.png) [@Huerta88](https://boards.straightdope.com/u/Huerta88)\
**Post date:** [August 21, 2008, 10:32pm UTC](https://boards.straightdope.com/t/how-does-body-hair-know-when-to-stop-growing/460859/4 "2008-08-21T22:32:01Z")

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Well I’m a dumbass and possibly a GQ rules violator. Sorry.

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**Author:** ![bytheway](https://avatars.discourse-cdn.com/v4/letter/b/df705f/32.png) [@bytheway](https://boards.straightdope.com/u/bytheway)\
**Post date:** [August 22, 2008, 12:56am UTC](https://boards.straightdope.com/t/how-does-body-hair-know-when-to-stop-growing/460859/5 "2008-08-22T00:56:45Z")

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Sometimes the hair cycle get messed up, because I have a single hair on my forearm that’s about an inch long. The rest of my arm hairs are 0.25 inch or less.