heres a quote from SuperTech69
"I like the results from QV250 but, I suggest you do not go with the 50ml bottle unless you are going to mix it with somehting as my injections are not mixed & are pretty painful. Supposedly it has a higher BA content for shelf life. I have a couple friends that have used the 10mls w/not much pain at all. I will stick with it even if I'm highly sensitive & have to mix it because it's inexpensive as hell."