I guess I've just been lucky with the IP oils...I've been using them for just about a year now...tried the sust, cyp, prop, eq, tren, durabolin, and deca. I've made considerable gains in that time and never had issue (at least from what I could tell) with dosing. As far as "dirty" goes, never had a problem with infection either. I did have a problem with the anti-e's though. Had to almost double my doseages on nolva and had to up the arimidex slightly.