Can Red Bull or other energy drinks give a false positive result on drug test?

I would not rely on it. Neither cranberry juice nor vinegar nor bleach nor any other household liquid can be relied upon to pass a drug test, so I don't see why Red Bull would be any different.

Red Bull is mainly water, caffeine, and B-vitamins. Some people swear that B-vitamins, especially niacin, can help you pass a drug test, but there is no reliable evidence to say that they do.

I'm guessing that the other reason people say Red Bull works is the caffeine: caffeine is a diuretic, meaning it dehydrates you by making you pee out a lot of the water in your body. So, you can see why someone would think caffeine would help: if it flushes out the water in your body, then it must flush out the drugs, too, right? Well, no. It may help flush the drugs out a little faster, but since you pee out most drugs (like speed, cocaine, Ecstasy, opiates) in about 3 days anyway, caffeine isn't going to help significantly.

Furthermore, marijuana is fat-soluble (it is stored in your fat cells) so no liquid will help flush it out of your body. To help get marijuana out of your system, you need to exercise. Exercise burns fat, including the THC that is stored in the fat.

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