Q: Ever since my heady liberal arts school days, I've been partial to sporting an “oops-I-forgot-to-shave-again” five-o'clock shadow. Generally, I’ve found that maintaining this popular-with-the-ladies look requires trimming two to three days a week in the winter. However, in the summer I've found that I need to trim four or five times a week. This seems ridiculous. Why would hair grow quicker during the hot months? It seems like it should be the opposite – growing faster in the cold months to keep us warm. What gives?

A: Well, I’m certainly glad that if you learned anything in your formative college years, it was how to rock that sexy, stubbly five o’clock shadow. Congrats — you’ve passed Facial Hair Maintenance 101. Your parents must be awfully proud.

Higher education aside, you’re definitely on to something with the grow-faster-in-the-summer phenomenon. I’ve noticed the same thing myself. During the dead of winter, I don’t need to do all that much on the facial hair trimming front, but during the sweltering months there’s been days when I’ve gone to bed looking like Kojak and woken up the next morning looking like Joaquin Phoenix.

So here’s the short, relatively straightforward answer to your question: Facial hair growth depends on the male sex hormone called dihydrotestosterone (DHT), the very same hormone responsible for male pattern baldness — this could be why you see some particularly hirsute-in-the face dudes who resemble sasquatches in need of Rogaine. During the sunny summer months, testosterone production is generally at its highest — well hello there, Vitamin D — which, in turn, frequently result in increased beardy goodness.

During the winter when most men actually want a thick beard, your body’s production of testosterone slows down and, in turn, that female-attracting stubble factory on your face lets go of a few seasonal workers. It all seems a bit ridiculous I know — you’d think when a man’s body goes into hibernation mode and the cashmere sweaters re-emerge from the back of the closet that facial hair would grow a bit quicker — but that’s the human body for you.

If you’re looking to correct this seasonal follicle imbalance and keep your mug warm during the chilly months, I’m not sure what to suggest other than experimenting with essential oils or picking up one of these beauties. Doctor-supervised testosterone therapy, including administering a topical dihydrotestosterone cream, might produce the desired results but that seems a touch extreme all for a more frequent wintertime five-o'clock shadow, don’t you think? It’s not like you can’t grow facial hair at all. I’d consider yourself lucky — some guys, particularly impatient teenagers, would kill for the chance to trim multiple times a week.

And on that note, happy trimming!

— Matt

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