[thedoc (OP)]

Why do eyebrows start to grow out of control in old people? I was at the barbers last weekend, and after cutting his hair, the barber asked the elderly gentleman in front of me if he wanted his eyebrows trimmed (they did need it!).
Asked by Andrew Steer, Cambridge


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[chapter podcast=1191 track=08.09.28/Naked_Scientists_Show_08.09.28_2565.mp3]  ...or Listen to the Answer[/chapter] or [download as MP3]

[thedoc (OP)]

We answered this question on the show...

We put this question to Des Tobin, Professor of Cell Biology, University of Bradford

[chris]

It's not just eyebrows though is it? Ear canals, previously glabrous, can become quite hirsute in the latter years, but mainly in men.

This leads me to presume it's got to have something to do with testosterone. I'm also not boasting about my virility, but my chest has definitely got hairier as I have got older (since post-puberty!) suggesting that lifetime testosterone exposure may be the reason.

Chris

[thedoc (OP)]

Listen to the answer to this question on our podcast.

[Ray hinton]

I have found that my hair has just re-located, moving from my head to my ears and nostrils  []

[Harry]

Hi all, this answer doesn't make much sense to me. It is well known that the testosteron level in elderly men is in decline and that's why a lot of elderly men go on a testosterone replacement program. In fact elderly men usually have too much oestrogene and not enough testosterone, that's why their old fella shrinks amongst other things. Also if testosterone makes our hair grow stronger then why do we lose hair on our scalp? I'm not trying to be critical but I don't think the given answer is very clear. I mean why do we lose the hair in places we want to keep it and grow it in undesired ones?

[Tanya]

I'm a female & us women as we age also find some strange increased hair growth, where once there was hardly any & visa versa... arrrrrrrrrrr!!! I hope my eyebrow hair never spreads to my ear canals... ewww!!  I bet some of my eyebrow hairs could be entered into the Guiness Book Of World Records. So unflattering & thank goodness for tweezers & facial grooming devices. I hear your pain fella. Looks like we are in this together. Happy Hairy Day to you all 😜