Niacin actually burns the thc out of your system. Just make sure to piss a lot before you take the test. My friend made the mistake of not pissing enough so instead of pissing clean piss, he pissed out all the thc that was burned. Let's just say for the level of thc that came up, he would have had to have smoked about an ounce to himself in the past couple days. Wow damn I forgot to make this post and I just left this box thinking I had already posted.