I have a test coming up in 2 weeks or so, pretty active, workout 3-4 days a week, but have been blazing for the past 2 weeks or so. I've had many friends take niacin with positive results. I've read that the reason niacin cuts down the time thc is in the body is because it expands the capillaries and allows more blood cells to flow through, which creates the flush that niacin gives. I've been taking 500mg everynight and the flush is really starting to piss me off, really bad itching, etc. If i take aspirin, the flush goes away. My question is, if i take aspirin, will this negate the detoxing effect of niacin? Or do my capillaries still expand..just doesn't make me itcha s much and stuff..? edit: beliefs aside, i don't want someone coming in here and saying "niacin doesn't work" whether its what you believe or not, I want to know whether the aspirin has an effect on the expansion of capillaries. Niacin alone wont' work, but combined with exercise and water it can do wonders for your metabolism.