Do energy drinks contain active components other than caffeine?

Abstract

Energy drinks (EDs) contain caffeine and are a new, popular category of beverage. It has been suggested that EDs enhance physical and cognitive performance; however, it is unclear whether the claimed benefits are attributable to components other than caffeine. A typical 235 mL ED provides between 40 and 250 mg of caffeine, equating to doses that improve cognitive and, at the higher levels, physical performance. EDs often contain taurine, guaraná, ginseng, glucuronolactone, B-vitamins, and other compounds. A literature search using PubMed, Psych Info, and Google Scholar identified 32 articles that examined the effects of ED ingredients alone and/or in combination with caffeine on physical or cognitive performance. A systematic evaluation of the evidence-based findings in these articles was then conducted. With the exception of some weak evidence for glucose and guaraná extract, there is an overwhelming lack of evidence to substantiate claims that components of EDs, other than caffeine, contribute to the enhancement of physical or cognitive performance. Additional well-designed, randomized, placebo-controlled studies replicated across laboratories are needed in order to assess claims made for these products.

Effect of Caffeinated Versus Noncaffeinated Energy Drinks on Central Blood Pressures

“…[6][7][8][9][10][11] Energy drinks are typically a mixture of caffeine and other purported energy-boosting ingredients, such as taurine, glucoronaolactone, guarana, and B vitamins. 12 It is not known if the reported serious adverse events are caused by overconsumption of energy drinks, combination with other stimulants and/or alcohol, a single ingredient (e.g., caffeine), or the myriad other ingredients in energy drinks. 13,14 Caffeine doses greater than 3 g have been associated with toxicity.…”

Energy Drinks, Caffeine, and Athletes

“…They found some weak evidence of increased sports performance for glucose and guarana extract but state there is an ''overwhelming lack of evidence to substantiate claims that components of energy drinks, other than the caffeine, contribute to the enhancement of physical or cognitive performance.'' 20 Heneghan and colleagues 21 at the Center for EvidenceBased Medicine at the University of Oxford, United Kingdom, reviewed studies on the effects of energy drinks on sports performance. The researchers noted that it was difficult to compare studies because they all used different subjects (some were exercise trained, whereas others were not), used different types of energy drinks in differing amounts, and did not always make the treatments isocaloric, and outcome measures differed.…”

Complementary and alternative medicine: Herbals and supplements: A review for the primary care physician

“…Consumption of caffeine and carbohydrates can increase alertness and performance if taken half to one hour before the desired time of effect. Patients with preexisting illness, such as diabetes mellitus and cardiovascular disease in particular, should exercise caution, as they may experience hyperglycemia and adverse cardiac effects [92][93][94].…”