I have talked w/several guys (most over 35) who have used it and it worked very well for them. Actually, of the 10 or so guys I've spoken to, I haven't heard any negative feedback (actually Vyo-Tech is a pretty good company). I would say that if you're not over 30 it might be a waste but, like I said I've never talked to anyone under 30-35 who have used it).
During the course of a day, the body only utilizes a small amount of their available testosterone. What the Dim does, is "free-up" testosterone levels, so you ultimately have more available in your system. Hope this helps. -BB