My boyfriend uses it and he gets a clean urine everytime he goes. But he does not take it everyday he takes it 2 hours before you go and drink about a gallon of water. Also take cranberry pills. It works.
Niacin works pretty good, but don't take it the day of the ua because they test for that too. If it comes out too diluted, they will suspect you of more and you'll have to take a blood test which is worse. Just drink a lot of water and exercise to sweat it out. You'll be fine.will slo niacin work to clean thc in a week