Your best bet is substitution. You can get a bottle of Quick Fix for about $20 online (try Amazon), and for the record, those GNC drinks WILL NOT clean your system. They rely on the dilution method, which you can do yourself (see sticky at the top of this forum) without having to spend the ridiculous $60 per bottle or whatever it is. Depending on your body type, you *could possibly* be clean in 20 days doing nothing, but if you NEED the job, I would definitely suggest getting some Quick Fix and subbing. Its your only surefire bet.