Definitely not good for chronic users! I stopped smoking 72 hours before the test and began drinking lots of water over the next three days--at least a full gallon each day, probably closer to two. On the morning of the test, I drank one glass of water every hour, stopping an hour before I was to take the product. Followed the directions (chugged the bottle, waited the 15 min and then filled with water and drank that, pissed three times in the next 45 minutes). I got to the drug testing facility about two hours after first consuming the TestPure Platinum and took the drug test. My urine was mostly clear. I tested positive for THC and won't be getting the job now. So now it's time to quit!