Yeah, they have to use stuff like EO and more BA/BB to hold it in solution. That is going to cause some major inflamation. Some claim to have use gear that was 400mg/ml or more and have no pain but I would have to be suspect of that because I have never personally witnessed such a thing. Usually high concentration=PAIN.
Heck, even when I was using over 2 grams a week it wasnt that big a deal having to inject 10ccs because that is just abit more than 3 syringes full. Just rotate sites. Much rather have 3 sites that were slightly to no pain than haveing 1 that was swollen to hell and so bad that I could barely walk.