TRT has literally changed my life. I've been on it for about 3 years now. My lethargy went away first. My energy levels increased next. Then I noticed increased stamina when doing physical activities. This was a tremendous help at shedding 60 lbs. The last thing I noticed six months in was libido. My girlfriend doesn't complain. ;) At 54, TRT has been life changing. I physically feel 30 again.