He's not taking testosterone from GNC...that would be illegal. He's taking some supplement that he thinks will raise his production of testosterone, but that product likely doesn't have much credible scientific support.
Do you suspect his testosterone is low or high? I couldn't gather from your comment.
M:12y - BD:12/11 - D:6/13 - 4Ds
"The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy." -MLK Jr.