If male pattern baldness is caused by testosterone, why are hairs on top of the head more affected by it and hairs like eyebrows, beard, inside ears etc, are affected less?

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If male pattern baldness is caused by testosterone, why are hairs on top of the head more affected by it and hairs like eyebrows, beard, inside ears etc, are affected less?

In: Biology

22 Answers

Anonymous 0 Comments

The general mistake here is to believe that every genetic trait is somehow designed to converge on perfection.

Frequently a trait – such as male pattern baldness – is a trade-off against another more important trait.

So, for instance, a genetic makeup that confers huge strength may also confer male pattern baldness. But the baldness is vastly outweighed by the advantages that huge strength carries.

Now factor in that the increase in lifespan has happened with disproportionate speed (because of technology). If you go bald at 40 but your aren’t expected to hit 30 because of the harshness of the environment, male pattern baldness – or any apparent disadvantage that manifests after the age of 30 – is irrelevant when it comes to giving you a reproductive advantage.

The relative speeds of evolutionary pressure isn’t enough to catch up with technological progress.

So here we are.

Anonymous 0 Comments

It may be because the scalp is quite a tough piece of skin, and has bone right below it, so hairs there don’t have a lot of soft flesh to cushion the follicles, or maybe the circulation is more unreliable

Anonymous 0 Comments

It’s affected by DHT (Dihydrotestosterone) a androgen created from testosterone via an enzyme known as 5 – alpha – reductase.

The effect of DHT is as an agonist for different androgen receptors found in various parts of the body.

On the scalp the receptors activated by DHT signal for hair loss where as in the pubic,facial and body it signals for hair growth.

Factors such as receptor quantity, sensitivity and 5-a- reductase activity determine the overall outcome of balding and facial/body hair.

Anonymous 0 Comments

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Anonymous 0 Comments

Is there an explanation for why the line on my head between the **will-never-grow-again** to **full-monk-band-of-hair** is SO distinct? It’s perfect, almost as if it has been hemmed into my scalp.

Anonymous 0 Comments

I think male pattern baldness is much more genetic then testosterone based. As I have a friend that has very low test levels (to the point they had to take pills to help boost their testosterone in their teens/early20s) but still started balding uptop by their late 20s.

Test levels are just a part of a bigger equation that is Male pattern baldness.

Anonymous 0 Comments

Is that why my hair is luscious and thick?

Anonymous 0 Comments

IIRC, it’s called the “androgen paradox.” The DHT causes hair loss on your head but actually causes facial hair and body hair to grow.

Anonymous 0 Comments

From what I understand, it has to do with how sensitive the hair follicles on your head are to DHT (a metabolite of testosterone)

Anonymous 0 Comments

From what I have learned…the hair on the head have a different testosterone receptor…which is absent in other parts of the body…so they fall off due to testosterone