Honestly not gonna lie, I do not know the answer to your question. But I am curious as well. I have heard that the quality of the gear can play effect such as "dirty" (low quality) raws etc. And then I have heard that some people just react differently at differently times or how potent the compound is. I do believe a lot goes into play, could be hormone levels, food you eat, sweat, could be tolerance to the substance, etc..
I have used some brands that I broke out a lot and then ran a different brands and it was not nearly as bad. I will say tho the best gains I ever had was on the gear that made me break out sooo really it just makes me think. But like I said, I will not act like I know, cuz truthfully I have no idea.