TweetI used to mix it right at the time before inject, just waited till it was clear solution. I later mixed two vials at once and never let it get to the point where I was injecting right after diluting it....This was only for time purposes. I didnt notice any difference in potency at all using either method. So I would mix it put it back in the fridge and come back in 15-30 min and shoot. Good question though, like to hear others methods