I know 3 competitors who tested positive for banned substances they stopped taking well within the safe range of those online charts. It really, really depends on the testing lab. Those charts are based on older testing methods, and the newer labs will catch ya if you're not extra conservative. I was sweatin' bullest the last time I got tested. I had been using norephedrine and yohimbine up until 7 days prior to the competition (hoping I wouldn't get tested but hedging my bets). Fortunately I passed the test, so I know that in MY system, 7 days is long enough to clear these drugs. Individual metabolism will vary.........