Here is a digest of relevant studies which prove that Red Bull stimulates metabolism:

1. Barthel T. et al., Readiness potential in different states of physical activation and after ingestion of taurine and/or caffeine containing drinks, Amino Acids 20, 1, 63-73 (2001)
2. Horne J.A., Reyner L.A., Beneficial effects of an “energy drink” given to sleepy drivers, Amino Acids 20, 1, 83-89 (2001)
3. Ivy J.L. et al., Cycling time trial performance improved by ingestion of a caffeine energy drink, International Journal of Sports Nutrition and Exercise Metabolism 19, 61-78, (2009)
4. Reyner LA and Horne JA, Efficacy of a ‘functional energy drink’ in counteracting driver sleepiness, Physiology & Behaviour 75, 331 - 335 (2002)
5. Seidl R. et al, A taurine- and caffeine-containing drink stimulates cognitive performance and well-being, Amino Acids 19, 3/4, 635-642 (2000)
6. Alford C. et al., The Effects of Red Bull Energy Drink on Human Performance and Mood, Amino Acids 21, 2, 139 – 150 (2001)
7. Geiss K.R. et al., The effect of a taurine-containing drink on performance in 10 endurance-athletes, Amino Acids 7, 1, 45-56 (1994)
8. Baum M., Weiß M., The influence of a taurine containing drink on cardiac parameters before and after exercise measured by echocardiography, Amino Acids 20, 1, 75-82 (2001)