Getting old sucks: You lose the hair on your head and sprout it from your ears and nostrils instead. But what is it about a bit of extra mileage that turns us into Chia Pets gone wrong? The answer lies within the hair growth cycle.
Hair grows in three stages: The anagen stage (that’s when the hair is actually growing out of your head); the catagen stage (when the hair stops growing); and the telogen stage (that’s when the hair falls out of your head). Hair typically grows in the anagen stage for two to six years before transitioning to the catagen stage, when the growth stops. A few weeks after the hair stops growing, it sheds during the telogen stage, then the hair cycle starts over again.
As we (men in particular) grow older, however, these stages are thrown out of whack, because some of our hair follicles will develop a sensitivity to dihydrotestosterone (DHT), a byproduct of testosterone that shortens the lifespan of each affected follicle. That’s why long-term exposure to DHT will eventually trigger full-on male-pattern baldness.
Paradoxically, DHT is also responsible for a surge in ear and nose hair growth (the scientific community fittingly calls this phenomenon the Androgen Paradox). DHT acts like steroids for the hair flowing from our ears and nose, which explains why they grow to troll-doll proportions without a regular trimming as we age. Put simply, DHT causes the hair on our heads to fall out, while causing the hair on our faces to grow wild.
Why DHT has such opposite effects on neighboring body parts is still something of a mystery, but at least we’re given a little time to prepare for the inevitable: Once you start losing the hair on your head, you can expect the hair growing from your ears and nostrils to look like the backend of broomstick just a few years later. Thanks a bunch, life!