Bad news for bearded men: scientists from the University of New South Wales suggests that we have reached "peak beard". Their new scientific study in journal Biology Letters warns that when beards are ubiquitous, people find them less and less attractive. In short, beards have become too popular for their own good. 

"The bigger the trend gets, the weaker the preference for beards and the tide will go out again," researcher Robert Brooks told the Guardian Australia. "We may well be at peak beard."

This doesn't surprise, fashion-wise. Beards haven't been sighted in abundance on the runway since AW12, where designers including Paul Smith and Umit Benan sent luxuriantly bearded men down the runways. Vivienne Westwood was so taken by the trend that she resorted to stick-on facial hair, adding an extra layer of faux-snow for added mountain-man authenticity. 

But researchers believe peak beard has more to do with human sexual selection than the fickle vagaries of fashion. In the experiment, test subjects (comprising of 1,453 heterosexual or bisexual women and 213 heterosexual men) were asked to rate different faces with four varying levels of beardedness. Both beards and clean-shaven faces became more appealing when they were rare. 

What's at work is an evolutionary phenomenon known as negative frequency-dependent sexual selection. Simply put, it just means that humans find rare traits sexier than those that are soooo mainstream. When faced with a crowd of bearded men, the clean-shaven one stands out. 

"These trends usually move in 30-year cycles from when they are first noticed but, with the internet, things are moving a lot faster,” said Brooks. “If guys aren’t getting any joy with their beards, they will quickly change.”