Any steroid will effect the HPTA, but 19-Nor's, tren and deca, will do it quickly, and often shut you down harder than other drugs. For any cycle, I suggest using some form of test as the base, and this is the reason why. The test will keep you functioning while "on" and allow you to function/feel as you normally would, if not amplify your sex drive. Some guys do have issues with estrogen, which can easily be controlled using an AI through the cycle. I would suggest .5mg adex, between 2x wk to EOD as needed. With 19-Nor based drugs, prolactin can become an issue from time to time, and if this effects your ability to perform, caber at .5mg 2x wk should turn that around. Because 19-Nor's can shut you down so hard, it is an especailly good idea to use HCG on cycle around 250iu 2x wk, to help ease recovery, once you come off. I would run the HCG through the cycle, right up to a few days before PCT starts. Remember, with Sust, you will need 3 wks to let the gear clear, before you start PCT.