Thousands of men across Britain are about to start growing moustaches in the next few days for Movember.
This fantastic annual charity campaign raises millions of pounds for charity and increases awareness of important men's health issues.
What is not so well known is just how many men in the UK struggle to grow beards or moustaches.
Recent research shows that as many as 45% of men in Britain cannot grow a full beard or moustache.
Beards have never been more popular.
Celebrities such as David Beckham, George Clooney and Ben Affleck have all encouraged men to ditch their razors and adopt the more hirsute looks of their favourite stars.
But how does a beard or moustache change a man's appearance?
And does that more hirsute look age men?
The team at Crown Clinic in Manchester thought it would be fun to find.
We assembled a panel of 300 people and showed them pictures
of various celebrities who constantly change their facial hair.
They were asked to guess how old the stars looked according whether they were clean shaven, had stubble, a moustache, a beard or a heavy beard.
Unsurprisingly, heavy beards, like the one recently worn by the soccer boss Roy Keane, aged men most markedly - adding ten years to his age.
Keane, who is 43, was adjudged to look 50 with his bushy beard. Clean shaven, he was said to look just 40 - three years younger than his real age.
Well-cropped beards put five years on a man's age.
David Beckham currently trims his beard.
The panel aged him at 35 - four years younger than his real age - when he was clean shaved. But he looked 40 with his current beard.
Twilight star Robert Pattinson is 28. He looked his real age with stubble but the panel said he was just 25 when he was clean shaved.
George Clooney often grows a moustache.
The panel aged him at 53 - his real age - with a moustache but just 48 when he had had a shave.
Brad Pitt, 50, often has a goatee.
The panel aged him at 49 with is goatee and just 45 when clean shaven - five years younger than his real age.
There is no doubt that facial hair and beards in particular do tend to make men look older.
But nothing ages a man more quickly than losing his hair.
Studies consistently show that men who go bald early in life suffer from lower self-esteem and can even earn less than men with full heads of hair.
Hairier men look more masculine but they also look older, especially if they wear their beard long like Keane or Ben Affleck
A lot of men grow beards to compensate for hair loss on their head. You see more and more who shave their head to cover up baldness on their scalp who then grow a full beard.
Some men who struggle to grow beards or sideburns even resort to facial hair transplants.
I often see men who want a transplant because their beard or sideburns are patchy. They feel like their masculinity has been undermined because they cannot grow a full beard like the stars they admire.
It is a relatively simple procedure to fill out a man's beard. Hair is taken from the back of the scalp and transplanted into the face where there are patches in the beard or sideburns.
The quantity of a man's facial hair is determined by genetics.
The truth is, you can have a very full head of hair and a very patchy beard and vice versa. That's just the way that genetics work.
If the father has a full beard there is a good chance that the son will have one, too.