Long time ago I was at a seminar by Craig Titus and Greg Kovacs.
Someone asked about creatine, and Craig started saying that all you need is 5 grams a day, and not to be fooled by labels that recommend anything greater, and that you can choose between its pure form or that mixed with sugar....then he jokingly said (this was while Greg was endorsing Muscletech), "Greg Kovacs uses the kind that is pre-mixed with sugar right?....that Celltech stuff?" and Greg had this sarcastic grin...both of them were implying that he doesnt actually use Celltech...everyone laughed...then they Greg goes, "actually some of Muscletech's products are pretty good, like the hydroxycut."
Overall from that I got the impression that they use very little/no supplements (other than protein powder) and don't necessarily use the brand they endorse, unless if they got it for free I'm sure they do.