He spoke to Showtime Joe Ferraro of Canada's Sports Net and here's what GSP said:
"When I first started fighting in mixed martial arts, it didn't have any money," St-Pierre explained. "So, now more money got involved, more ways are there to be cheating to take a shortcut and I believe VADA testing I'm up for it and I invite my opponent to do the VADA testing for the championship fight.
"I invite if possible all the high-profile athletes in the UFC to do the same. I believe it's a good thing. It's a bit of a pain in the butt sometimes but I believe to make the sport (better) ... I'm ready to do it to set a good example."