I had a few clients (not of HRT) run it for 8-12 weeks and other running it for 5 weeks on 2-3 off. People who ran it longer testosterones had singificantly lower testosterones at the tail end of the cycle. As for studies on people on HRT, I have a feeling it may help HCG in many cases as well as increases in estrogen if one is sensitive. I prefer to stay off HCG due to the trade off of e2 is not worth it for me even if at 250 ius 2 times a week. Being off HCG has result in morning wood on a daily basis, less emotional swings, better quality of sexual activity (no PE) Being on HCG and adex was not as consistant as performance wise. I will research for studies which are recent. I have found ones from 2009, but nothing with a few months or updated. I did have a guy using 3.5 grams of DDA and was at low T 300's then after 4 weeks shot up to 700 with out HCG.The only problem I see is that body gets used to it and needs to be cycle to have optimal effects. Here is the amazing thing the e2 did not go up significantly which was very interesting. Could the DAA actually replace clomid in the future once the half life and more studies are conducted..Potential is there, but long term effects are still unknown..