There is a growing body of lit that suggests that the 19-nors are the most neurotoxic (all AAS even T at some point will become neurotoxic), Tren falls in that box for sure. We don't have years of clinical data on Tren like we do ND that has been used clinically for decades. Estrogen and DHT appear to be neuroprotective, one reason T is the best all around base drug. Warhead nailed it, Test, Primo, Mast and Var if the plan is long-term enhancement would likely present the lowest risk, esp if the base (cruise) was mostly T with perhaps some Mast and maybe a little ND (50 - 100 mg/wk) if you're one of those guys that really does get some joint relief with it. There was a study done in 1973 on Mast P for gyno, 50 mg/wk, it shrunk the gyno. There was no effect on LFTs or other blood chems. IMO, just my thinking, a good base high end HRT would be 100 - 150 TC, 50 mg MP and 30 - 50 mg ND (total) per week done with EOD dosing (not to exceed 250 mg total a week). If E2 becomes a problem add a little more MAST and cut back the T a little to find that balance without an AI. Minimize the C-17's and stick to VAR if you use them. Obviously, get blood chems 2 - 3 times a year and an echo baseline and maybe every other year, liver US if you use the C-17's.