# Why does some hair lengthen indefinitely, while other hair reaches a certain length, and then stops? **URL:** \ **Category:** Factual Questions\ **Created:** [March 26, 2018, 4:09am UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189 "2018-03-26T04:09:54Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Steven\_Estes](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@Steven\_Estes](https://boards.straightdope.com/u/Steven_Estes)\ **Post date:** [March 26, 2018, 4:09am UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/1 "2018-03-26T04:09:54Z")
Why does the hair on some parts of your body lengthen indefinitely, while the hair on other parts of your body reaches a certain length, and then stops? ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 26, 2018, 4:56am UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/2 "2018-03-26T04:56:24Z")
Neither is true. Hair grows for a time, then becomes dormant for a while, and then falls out. The difference in the length of hair on different parts of the body is because it grows for different lengths of time before falling out. Head hair doesn’t “grow indefinitely,” but it may grow for years before falling out, so it can get quite long. Body hair instead only grows for a few weeks before falling out, so it never gets very long. Different people may also differ in how long their hair grows for. That’s why some people’s head hair can get much longer than others. [More on the subject from the Perfect Master.](https://www.straightdope.com/columns/read/90/how-does-body-hair-know-its-been-cut-and-grow-back/) ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [March 26, 2018, 11:15am UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/3 "2018-03-26T11:15:04Z")
My chest hair used to stop growing, once I got past 40 it never stopped or fell out. Now it will get over 12" long if I don’t cut it. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [March 26, 2018, 12:48pm UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/4 "2018-03-26T12:48:51Z")
> [@HoneyBadgerDC](#): > > My chest hair used to stop growing, once I got past 40 it never stopped or fell out. Now it will get over 12" long if I don’t cut it. Especially during full moons when you are the werebadger. **Colibri** got it in one of course but **HoneyBadgerDC** ’s perceived experience still raises another question: certain body hair seems to switch of time, growing longer before going dormant and not falling out (which means a new cycle of growth is beginning underneath) for quite a while, his chest hair for example, and those ear hairs that start to grow long at middle age and beyond. What about the aging process changes the hair growth cycle? ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [March 26, 2018, 2:22pm UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/5 "2018-03-26T14:22:24Z")
Another vote for **Colibri**. As I have mentioned before, **DesertRoomie** has not cut her hair since she was out of her mother’s control at age 17. She wears it in a braid to protect it and has only trimmed a quarter-inch or so maybe every couple years to stop the split ends. When not in the braid it reaches down to her butt. She’d love if it was longer but that’s what she gets, way short of the six-feet or more that I have read about with some women. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [March 26, 2018, 4:53pm UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/6 "2018-03-26T16:53:28Z")
Ear hair gets longer. Especially since I aged past 50. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [March 26, 2018, 5:07pm UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/7 "2018-03-26T17:07:41Z")
Fun fact: your hair, even while on your head, is excreta, just like the other stuff. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 26, 2018, 5:38pm UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/8 "2018-03-26T17:38:27Z")
> [@Leo\_Bloom](#): > > Fun fact: your hair, even while on your head, is excreta, just like the other stuff. Not according to any normal definition of excreta. Excreta are normally defined as the waste products of digestion that are excreted from the body. Hair does not fit that definition. ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [March 26, 2018, 7:03pm UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/9 "2018-03-26T19:03:35Z")
> [@aceplace57](#): > > Ear hair gets longer. Especially since I aged past 50. I am convinced that for men, hair migrates from head to ears and back as we age. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [March 26, 2018, 7:05pm UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/10 "2018-03-26T19:05:46Z")
> [@Colibri](#): > > Not according to any normal definition of excreta. Excreta are normally defined as the waste products of digestion that are excreted from the body. Hair does not fit that definition. Thank you … **Colibri** … may your coat glisten in the moonlight … ---
**Author:** ![Disheavel](https://avatars.discourse-cdn.com/v4/letter/d/e274bd/32.png) [@Disheavel](https://boards.straightdope.com/u/Disheavel)\ **Post date:** [March 26, 2018, 8:40pm UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/11 "2018-03-26T20:40:02Z")
> [@HoneyBadgerDC](#): > > My chest hair used to stop growing, once I got past 40 it never stopped or fell out. Now it will get over 12" long if I don’t cut it. Holy smokes! That’s what happened!!! ---
**Author:** ![TSBG](https://avatars.discourse-cdn.com/v4/letter/t/77aa72/32.png) [@TSBG](https://boards.straightdope.com/u/TSBG)\ **Post date:** [March 26, 2018, 10:21pm UTC](https://boards.straightdope.com/t/why-does-some-hair-lengthen-indefinitely-while-other-hair-reaches-a-certain-length-and-then-stops/811189/12 "2018-03-26T22:21:29Z")
Since the original question was asked and answered, can I chime in to ask a related question about hair growing at different rates? This is all anecdotal of course, but I don’t shave my beard every day because I don’t have to, but when it gets too long it annoys me. Time from shave to annoying seems to vary from two days to four days according to no factor I can identify. Same applies to my head hair, which I keep trimmed close–sometimes I need a touch up after a week, other times I can go two or even three weeks before it starts to look ratty. I know hair growth is to some extent regulated by testosterone, but are my hormone levels really fluctuating that much? Wouldn’t I have other problems if that were the case?