Norephedrine/Ephedra Sinica

How long does it take for norephedrine or ephedra sinica to get completely out of your system? (I know they’re two different things, I’m asking about both because I have bottles of the old MD6 formula, and I was thinking about either using it or ordering some of the new stuff). I’d like to use MD6 to help drop some weight over the next few weeks, but don’t want to get screwed during a drug test just because I used MD6 to help me drop a few pounds.