Taurine, an amino acid important in several of the body's metabolic processes, is thought to have antioxidant properties. But little is known about the effects of long-term supplemental taurine use.

Taurine is found naturally in meat, fish, dairy products and human milk, and it's also available as a dietary supplement. While research is mixed, some studies suggest that taurine supplementation might improve athletic performance. And, in one study, people with congestive heart failure who took taurine supplements three times a day for two weeks showed improvement in their exercise capacity.

Other studies suggest that taurine combined with caffeine improves mental performance. However, further research is needed and this finding remains controversial, as does the use of taurine in energy drinks. Keep in mind that there might be high amounts of other ingredients in energy drinks, such as herbal stimulants, caffeine or sugar. Too much caffeine can increase your heart rate and blood pressure, interrupt your sleep, and cause anxiety. Added sugar might provide unwanted added calories.