Case of four 8.4 fl oz Red Bull Sugar Free cans. Red Bull Sugar Free’s special formula contains ingredients of high quality: Caffeine, Taurine, some B-Group Vitamins, Aspartame & Acesulfame K. One 8.4 fl oz can of Red Bull Sugar Free contains 80 mg of caffeine, about the same amount as in a cup of home-brewed coffee. Vitalizes Body and Mind.