For me, I believe it is a combination of good a E2 level and NO. I have not doubt that NO plays a huge role in effectiveness of erections. Since I've been taking supplements for my NO my erections have improved dramatically. If I don't have nightly/morning wood then I know one of the two is out of wack.
I take 400IU HCG EoD, and 6 to 9 grams of Citrulline Malate 2:1, and 5 grams of L-Arginine daily. To control the E2 I take .125 grams AI E3.5D with my Test E shots (60mg each).
It's not unusual for me to forget to take the AI. If I feel emotional during the week I know I forgot to take one or two that week. I take one and wood comes back the next night/morning. I generally have a couple/few left over when I need to reorder my HCG and AI.
