I had smoked marijuana every day for the past month. Before that month I was very clean. I have boughten 5 thc tests from the internet. They all have the 50 thing limit to it like all the probo's tests are. So I mixed certo(1 packet) with a half gallon of water. I pissed till my bladder was empty. I have taken a1 b-complex pill, then i took 2 aspirin at like 5:05 pm. I then started to jug the certo mixed water at 5:10 pm, gotten done at 5:35 pm. 20 minutes later i had to piss. These pisses are all midstream. The first piss i did was dirty. Second piss was clean.(pretty faded) Third Piss was clean but had a more visible positive. Second piss was alittle yellow, but the third piss was much more yellow. I was clean by 6:10 PM. So my conclusion is that this method works. It could be much more yellow to have a more convincing look, but it was yellow enough to not be questioned. So I would have gone with 2 b-complex pills instead and taking it like 10 minutes before drinking certo. And make sure you pissed a couple times before pissing for the test. I was amazed at the results since I had a very high thc count in my system. So this method is my recommended method. They could test creatine levels but just take creatine supplements if your worried. I dont have to worry about that where I live. Cheap state. Peace, Korado