Morning Hell! - please help?

My 4 year old daughter is unbelievable in the mornings! She is so sleepy and sluggish, and will not move for me. I was watching Toddlers and Tiaras on TV and the mother gave her daughter at least 2 cans of Red Bull (brand name was blurred out, but it was obviously Red Bull) to get her moving. I have bought some today and was thinking of trying it on Monday... my friends have mixed opinions on this. It's available for sale to kids so surely it's not harmful?