Sonnes #7 has worked for me and many other hardcore heads but, it's still a scary gamble. Abstinance is best ;-) If it's too late for that here is what I have done for the past 20 years: If you know a urinalysis is coming and you have time just go to urineluck.com it is WAY better than Sonnes. These people stay ahead of the testing labs and will even upgrade older versions if you have them. Back to the Sonnes idea (which is what I use most) A few days before the test you should be eating/drinking mass amounts. This will flush you and keep you from burning a lot of new fat at the same time. I usually do a 30-pak of cheap beer (Beast!) and eat lots of pasta for a few days and then take a few spoons of Sonnes the night before and the morning of the test. If you know about the test within 4 days or longer start exercising like mad. I do 4-8 mile walks and drink lots of fluids, especially water, coffee, and beer. Then when the last few days draw near I shift into sloth mode to stop the fat burning.