Taurine is an organic acid naturally present in our bodies that supports neurological development and regulates the balance between water and minerals in the blood, which makes it a potential antioxidant. You can get taurine in meat, fish, and breast milk; and also as a dietary supplement in energy drinks.
Energy drinks contain caffeine, taurine, and glucose, combo that has been proved to improve information processing in individuals who could not have been in caffeine withdrawal. In this study, 42 participants were tested with a rapid visual information test, a verbal reasoning test, a verbal and non-verbal memory test and a set of mood measures. Prior to testing, they were allowed to consume energy drinks until 1 h before testing (study 1) and unrestricted caffeine use before testing (study 2). In both studies, the caffeinated, taurine-containing beverage produced enhanced attention and verbal reasoning, in comparison with a sugar-free and the sugar-containing drinks. The relevant improvement with the drink was manifested in terms of both the mean number correct and the reaction times.
In this other study, though, feelings of well-being, total scores, vitality scores and social extrovertedness scores were significantly higher in energy drink group (specifically, Red Bull), in contrast to the placebo one. Different studies have repeated these procedures with the same consistent results: energy drinks do improve cognitive performance, at its least.
Nevertheless, the findings suggest that most of the effects of energy drinks on cognitive performance are related mainly to the presence of caffeine and glucose. When taurine was isolated, cognitive performance did not show the same enhancing effects, suggesting that taurine is not responsible for these temporal benefits. In the same line of thought, researchers created a glucose-caffeine-exclusively “energy drink”, and the amelioration of deficits in cognitive performance due to subjective fatigue were the same as the ones found in the taurine condition. No additional benefit was found.
In conclusion, while energy drinks do work, they are probably not doing better than your regular cup of coffee. Thus, the decision between a red bull and a double espresso would be one of taste and money (an energy drink normally double the price of a regular coffee!).