Im not sure why you are getting this fatigued feeling while on one brand but not the other. A lot of steroid use is trial and error. Its possible your body has an allergy to one of the solvents used in one brand. This is the kind of thing you may never have an answer for but there is a simple solution. Just stick with the brand that feels good. After all, the goal of all our experimentation is to find out what works for you. Some guys will do better with Deca while others do better with EQ. Some guys will respond well to one brand but possibly not the other. Also whenever you are in question about whats happening in your body, you can always get labs done and its pretty cheap. Maybe $70 to have done privately. Search ”private lab work” and you’ll find sites like Private MD Labs which will get your results back in just a couple days. For now though, I would just stick with the brand that os working for you.