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By: David Larson, MS, CSCS

Since the introduction of Red Bull in the United States in 1997, the use of energy drinks as a way to ward off drowsiness and as an ergogenic aid has risen tremendously. As of today, the United States alone consumes over 290 million gallons of energy drinks every year, with the numbers increasing every day. Upon glancing at the labels of such beverages, one would be lead to believe many of the drinks can be used to promote health and performance; however, one must remember that the United States does not regulate or place any restrictions on what energy beverage companies claim their products do.

This raises the question of what effects such beverages have on the body and weather the suggested benefits outweigh potential side effects. In order to decide if a particular energy drink is appropriate to use, one must consider several different variables and have a thorough understanding of the contents of different energy drinks.

Main Active Ingredients Found in Energy Beverages:


Caffeine is easily the most well-known and most common ingredient of most energy drinks. It has been shown in numerous studies to improve mental sharpness, improve performance, and delay fatigue Improved performance is generally attributed to the sparing of muscle glycogen due to the increased mobilization of fat stores during exercise with caffeine.

Peak levels of plasma caffeine following ingestion occur in approximately 30 minutes and the effects last between about 3 to 10 hours. Although these performance benefits appear substantial, the effectiveness of caffeine in improving performance is equivocal. Because the body quickly develops a tolerance to caffeine, it is often difficult to judge whether benefits are tolerance related.


Guarana seeds have long been used by the Amazonians to augment energy and wakefulness. Guarana contains the most caffeine of any other plant, along with other potent stimulants such as theobromine and theophylline. Interestingly, many companies do not list the caffeine content of guarana on the label, which means one may end up consuming much more caffeine than intended.

B Vitamins:

B vitamins are found in nearly every energy drink in various amounts. B vitamins are necessary to convert the energy in food into ATP, the energy currency of cells. Although several companies market the high B Vitamin content in energy drinks as a way to increase energy, taking in these excess amounts will not likely translate to increased energy unless a preexisting deficiency exists.

Deficiencies in the general population appear unlikely, however, considering the majority of people get all the B vitamins needed though diet alone. For example, the National Institutes of Health Office of Dietary Supplements indicates that only about 10 micrograms of a 500 microgram oral supplement of vitamin B-12 (about 2%) is absorbed in a healthy adult.


Taurine is an amino acid found in animal tissues. Taurine has several important biological roles such as bile acid conjugation, membrane stabilization, regulation of hydration and calcium signaling; however, most benefits will not be seen at the levels found in most energy beverages. There is evidence that simultaneous supplementation of taurine and caffeine can have an ergogenic effect and positively effect well-being.

On the other hand, it has been suggested that taurine supplementation could act as an energy suppressor, rather than an energy enhancer. Furthermore, it has been demonstrated that taurine can reduce the excitability of thalamic relay neurons in vitro (Jia et al., 2008). This may contribute to the “crash” that many people experience following energy drink consumption.


Carnitine is produced mainly in the kidneys and liver and aids in increasing metabolism. Results of studies on carnitine supplementation are mixed. It has been shown that carnitine supplementation can increase VO2 max and lower the respiratory quotient by stimulating lipolysis; however, numerous other studies show no benefit in healthy adults, as endogenous carnitine production appears to be sufficient for even the most demanding exercise (Brass et al., 1998; Brass, 2004).


Sugars are the body’s fundamental currency for energy. Sugars are usually found in energy drinks in the form of sucrose or high-fructose corn syrup. Administration of carbohydrate solutions in sports drinks (4-8%) before, during, and/or after exercise has been shown to improve endurance performance and aide in recovery; however, sport drinks are designed to mirror blood osmolality to promote rapid absorption and fluid retention.

Energy drinks, on the other hand often have osmolalites of several times what is needed for optimal absorption. This may lead to slow gastric emptying and gastrointestinal discomfort during exercise. Furthermore, because popular energy drinks contain such high amounts of sugar (over 1/4 cup), it may contribute to the increasing incidence of metabolic syndrome and obesity.


Ginseng is an herbal supplement used to treat and/or prevent numerous conditions. It has been suggested that ginseng can increase energy, alleviate stress, and improve memory by facilitating greater corticotropin release from the hypothalamic and pituitary glands. On the other hand, it has numerous reported side effects when taken at high doses. However, the dosages usually found in energy drinks are generally under the amounts needed to deliver the purported benefits or side effects.


Glucuronolactone naturally exists in small amounts in the body. Supplementation appears to help eliminate carcinogens and tumor promoters; however, there does not seem to be enough human studies to determine the efficacy of supplementation.

Although many commercial energy drinks are marketed as a way to promote health and increase energy, there appears to be substantial evidence indicating the opposite. Furthermore, the added sugar content of most popular energy drinks is likely to contribute to the increased incidence of metabolic syndrome and obesity.

Those interested in energy drinks should use caution when making their selection and avoid products that use excessive amounts of any ingredient, vitamin, or mineral. The best energy drinks are likely those with a low sugar content, organic ingredients, and food sourced/bioavailable vitamins and minerals.


Higgins, J. P., Tuttle, T. D., & Higgins, C. L. (2010, November). Energy beverages: content and safety. In Mayo Clinic Proceedings (Vol. 85, No. 11, pp. 1033-1041). Elsevier.

Ishak, W. W., Ugochukwu, C., Bagot, K., Khalili, D., & Zaky, C. (2012). Energy drinks: psychological effects and impact on well-being and quality of life—a literature review. Innovations in clinical neuroscience9(1), 25.

Mettler, S., Rusch, C., & Colombani, P. C. (2006). Osmolality and pH of sport and other drinks available in Switzerland. Schweizerische Zeitschrift fur Sportmedizin und Sporttraumatologie54(3), 92.

Geiss, K. R., Jester, I., Falke, W., Hamm, M., & Waag, K. L. (1994). The effect of a taurine-containing drink on performance in 10 endurance-athletes. Amino Acids7(1), 45-56.


DSC_0215-32 David Larson is a trainer at Pulse Fitness in North Scottsdale.  He holds a Masters of Science Degree in Kinesiology from A. T. Still University, graduated magna cum laude with a Bachelors of Science degree in Kinesiology from Arizona State University, and is a Certified Strength and Conditioning Specialist through the National Strength and Conditioning Association. 




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