Prince William appears eight years older than his real age because of his hair loss, according to a new survey.
The 37-year-old heir to the throne has the looks of a 29-year-old man if he had taken steps to address his hair loss
That is because balding ages men more quickly than any other physical trait - putting up to eight years on the age of sufferers.
The second fastest ageing factor is greying hair which puts seven years on the age of the average man.
It means a silver-haired star like George Clooney would look 51 rather than his real age of 58 if he were to start dying his hair.
The third fastest ageing trait is having a full beard - which puts five years on the age of men.
So 44-year-old David Beckham would look 39 if he were to have a shave.
The fourth biggest ageing factor was having a goatee which ages men by four years.
Hollywood actor Leonardo DiCaprio looks 41 when he is clean shaven but his real age of 45 when he is sporting a goatee.
The fifth biggest ageing factor is being heavily unshaven, like Simon Cowell on the X Factor, which ages men by three years.
So Cowell would look 57 if he shaved rather than his real (unshaven) age of 60.
The findings came from survey of 1,000 people by Crown Clinic in Manchester, Britain's leading hair transplant centre.
Other ageing factors include being overweight, having man boobs and sporting a moustache, which all age men by an average of two years.
Hair transplant surgeon Asim Shahmalak from Crown Clinic said: "Nothing ages a man faster than losing his hair.
"Prince William was one of the most desirable men in the world when he was in his early 20s but he has aged fast because he has done nothing to remedy the Windsors' strong baldness gene which has also affected his father and his grandfather.
"Wayne Rooney has turned back the clock very successfully by having two hair transplants. Just image how much less attractive he would look to sponsors if had let nature take its course.I am sure it has also helped to prolong his football career because he looks younger and fresher with hair."
Dr Shahmalak is Britain's leading hair transplant surgeon and his celebrity clients include model Calum Best, TV doctor Christian Jessen and Chris Steed, star of Gogglebox.
Around 80% of his patients opt for FUE because it leaves less scarring than FUT.
Dr Shahmalak has seen a 25% rise in young men seeking hair transplants since Rooney had his first procedure eight years ago.