How old is your friends?
I tried Tribex (was 21 at the time) - I'm 25 now. Didn't feel like tribex did anything at all for me, nothing, I've tried other pro-hormones when they were still legal like Andro and M1T - definitely felt like they work.
If your friend is a competitor and he decides to use tribex just be careful cause it can throw off your T/E ratios and make him fail a drug test.
But like I said, I didn't feel anything at all from it!