But the former All Blacks star was facing one of his toughest challenges this month - growing a moustache to raise awareness about mental health.
"I can't grow a strong mo' (moustache)," Carter, who normally only has to shave about twice a week, said on Thursday.
"I have done bits and pieces over the years but never committed to growing one for a month.
"It's been just over a week and it's pathetic really."