Ive been a pot smoker for about 15 years till i scored a wicked job and job site policy is to do random drug testing on site... they pick you out as you come in the gate.... I've been taking Red bull and Berocca with vitamin B2 & B3 every morning all i can say is so far so good..... I drink water till i'm pissing clear then take the above mentioned items about an hour before i walk through the gate....