I am on HRT and inject testosterone twice weekly. I also take an aromatase inhibitor do keep the estrogen in check. Testosterone does convert to Estrogen, and when its too high it counteracts the effects of the T. The brand name is Arimidex. My T levels are about where a 17 year old males would be. My estrogen was way off the chart and the Arimidex brought it down into the low/normal range. I wouldn't use T without keeping the E in check. Felt like crap with the high E.