The 43-year-old admitted that he is aware of his good looks but is already experiencing signs of ageing.
"I know I'm good-looking, but I'm not egotistical," he told Heat.
"I have flaws - I have to dye my hair twice a month to get rid of all the grey. But I also have these eye-flaps and bags. And I have a problem round my stomach... I have let myself go in the waist area. When I see myself naked, I know I'm heavy and out of shape."
He added that he does not believe that cosmetic surgery has to be a negative thing.
"If the time comes and I want to go under the knife, I'm going to go and do it. If it makes someone feel better - as long as you don't come out and you look like you've been tied up from behind your head, or that you have to speak out of your arse - it's fine."
Barrowman recently revealed that he hopes to return to his role on Desperate Housewives.