It’s official, grumpy old men are real. That’s the message from the head of the International Society of Men’s Health. Men of a certain age have always had the stereotype of being grouchy. That’s why they’re often shown in movies with scowling faces, while they complain about teenagers, and say things like: “Get off my lawn!”

But it turns out, there’s a reason for that grumpiness.  In fact, scientists have a name for it: “Irritable male syndrome.” And according to doctors, it tends to start kicking in after about age 60. Why?

Well, a lot of it boils down to the fact that as men age, their testosterone levels drop. And because testosterone is the hormone that affects energy and mood, having low testosterone often leads to bad moods and irritability.

But another factor that contributes to grumpy old men is that men are less social than women. Experts say women tend to be comfortable talking to each other.  In fact, Oxytocin – the hormone that reduces stress in women – is stimulated through communicating.  While men, on the other hand, need testosterone to feel less stressed. And extra testosterone isn’t produced through communication. That explains why men may be more irritated, and have less tolerance for other people.  Because low testosterone is liked to problems with concentration and tolerating the ups and downs of everyday life.

Also, when men retire, that can result in depression, because they no longer feel valuable to society. So, if you’re a grumpy old man, it may be time to start communicating more, even if it’s just to gripe. And stay active and involved in projects post-retirement.