Replying to Alright so its drug test time

Don't say search cause i have and came to the following conclusions:

1. Buy some shit at a head shop and drink tons of water and you'll be fine for 5-7 hours. But is this guaranteed? Who's done it and passed it.

2. Go to GNC or something and buy niacin. Take 3-5 pills a night for at least a week b4 the test and drink tons of water. But how many mg are the 3-5 pills? And can i still smoke during that one week? Has anyone actually done this themselves and passed?

Excercising is out of the question becasue i have a torn acl and shit. And plz don't say ur fucked or go cut ur dick off like the other threads have said haha. And id rather not tape someone elses piss to my arm or some shady shit like that b/c ive heard of temperature issues and the fact that its just shady as hell. Thanks for any help i can get, i can't afford to fail this drug test.