Hi, I Have To Run 1 1/2 Miles In 17

Hi, I have to run 1 1/2 miles in 17 min in two weeks for a job that requires us to pass for the agility test. I have been practicing but my breathing slows me down. I researched and found beet root is good for runners to enhance their performance. I found "Ultra Beet Root Performance Powder" in my local supermarket and took my first glass today following the directions of 1 tablespoon daily. Will taking this cause me to have a positive result when I take the toxicology test which is also a requirement for this law enforcement job?