Niacin, in the short term will do nothing to help pass a drug test, urine or hair. The myth goes back to a clinical study done by L. Ron Hubbard, the Scientoligist. Do a google for 'L. Ron Hubbard and niacin research'. In the study, done to remove traces of LSD and end flashbacks, a regiment of excersize, saunas and Niacin was used, over several months. The results indicated that ALL toxin trace eliments could be removed this way, including THC. Thus the myth was was born that Niacin will clean out THC. Hope that clears thing up. N2