I'm not a heavy smoker. Maybe once a week for the last couple of months. Haven't smoked in ages before that. I weigh about 200lbs. I used xxtra clean detoxify tropical flavor for larger body mass and it worked for me. Granted it does not cleanse your body of toxins forever but it worked as it said it would. It gave me a window to test clean. I did not follow the instruction on the bottle. The head shop I got it from taped their own instructions on the box. They said you should be clean for at least 48 hours before the test for best results. Luckily I had smoked on a Saturday night and found out Monday afternoon that I had to take the test the next day. Start 90 minutes before test by drinking the bottle. I did so in about 15 minutes. Then wait 15 minutes and fill the bottle with water only once. If you drink too much water you will test diluted. Drink it and then wait 1 hour before taking the test. During the wait pee at least 3 times. Done. Clean for next 5 hours. I peed 4 times before the test and took it about 2 hours after I started the process. Another thing, I took an at home drug test using my second void. The test said I passed with a dark line in the THC window. I was freakin out after reading all these posts about how the drinks don't work and had a long, agonizing wait until I got the results. I tested at Labcorp and they sent the sample out for lab testing. It was not done on site. Hope this helps some of you to relieve some of the anxiety that comes along with the wait.