Quote from 2manywhiners:
I'd go with GNC's & MuscleTech's stuff and do the exercise. Besides, supplementing with any product that raises testosterone without exercise (herbal, prescription, or otherwise) will lower your body's natural production of testosterone which is going to bite you in the ass down the road when you stop producing testosterone all together. Do the work and get into better shape along the way.
VERY important point, from studying endocrinology I have always been extremely resistent to the idea of external tampering with hormones - they are all linked together via feedback loops and the body can be fooled into thinking it needs to shut something down if serum levels are artificially high - testosterone is a known case of this. At late fourties/fifties maybe the benefits offset the risk, but before the age where natural slowing of production kicks in to the point of affecting quality of life I would be very wary of taking testosterone. That is why I have not taken it yet even though i can buy it OTC.