(quote from Redbull)
Is Red Bull Energy Drink halal?
Red Bull® Energy Drink is halal. This has been certified by the MUSLIM JUDICIAL COUNCIL. Imaam Y. Harris, Cape Town. Before issuing this certificate the production site and the origin of the ingredients were inspected and checked by an official of the Federation.
this doesn't make it halal or haram yet but, as per the information on their website the product according to them is Halal/Kosher/Vegan friendly... further questions are being asked...
So far http://eathalalfood.blogspot.com/ has not found any REAL reasons to enlist this product under the haram category...
If somehow someone that actually works inside the company.. specially someone that oversees the manufacturing process provides information, it might be possible to reach a definite conclusion.