Yes it reverts your body back to your late teens in a lot of ways. Appetite, metabolism, sex drive, muscle building and recovery really amp up. I was doing cardio and tracked my heart rate. After starting only a small dose of testosterone I notice that my heart rate wasn't quite as high. I had to work harder to get it there. It didn't take as long to recover from sets, and of course
I added muscle. You can see why this would be appealing to athletes. I've done several cycles of test (both enanthate and cypionate) and it has worked very well for me every time.