Q. I’ve noticed that at my local gym, the men who regularly workout have either thinning hair or are bald. What’s up with this?

A. When men exercise, there is a hormone that comes out on the scalp. This hormone (called DHT for the most part) is what triggers the balding pattern in most men. These men you see that are “thinning and/or balding” are the guys who don’t shampoo immediately following their workout. By leaving this DHT hormone on the scalp surface, 
they’re allowing it to sit and work against them. If these are your friends, suggest they start showering before leaving the gym (they’ll smell better, too).