Share this article on:

Question Authority

Nieman, David C. Dr.P.H., FACSM

doi: 10.1249/FIT.0b013e3181b481a9
DEPARTMENTS: You Asked For It: Question Authority

I enjoy energy drinks, but wonder if the high amounts of caffeine are harmful to my health. What do you recommend?

David C. Nieman, Dr.PH., FACSM, is professor and director of the Human Performance Laboratory, Appalachian State University, in Boone, North Carolina; an active researcher; and author of several textbooks on health and fitness. Email your questions to


A: During the mid-1980s, the Austrian Dietrich Mateschitz started selling Red Bull energy drink, which quickly spread throughout Europe and then the world, including the United States, in 1997. Dietrich got the idea when sampling tonic drinks in Hong Kong. Red Bull remains the top name in energy drinks to this day, with global sales estimated at about $3.5 billion annually. Scores of other similar products have flooded the energy drink market including Monster, Rockstar, Full Throttle, and NOS Powershot.

Generally, energy drinks include caffeine, B vitamins, and herbs. Other common ingredients are guarana (a plant from Brazil high in caffeine), taurine (an organic acid touted for various mental effects), plus various forms of ginseng, sugars, carbonated water, and other special ingredients, such as Ginkgo biloba, that supposedly influence the mind. Some contain high levels of sugar, and many brands also offer artificially sweetened low-calorie versions. One can of Red Bull is 110 calories, whereas the low-calorie version is 21 calories.



The central ingredient in most energy drinks is caffeine, the same stimulant found in coffee or tea, often in the form of guarana or yerba mate. The average 1 fl oz portion of energy drink has about 10 mg of caffeine, but some are much higher, including 171 mg for Ammo, 62.5 mg for NOS Powershot, and 33.3 mg for Cocaine Energy Drink (see Table). For comparison, 1 fl oz of coffee has about 13 mg caffeine whereas Coca-Cola has 2.9 mg. The amounts of taurine, ginseng, and similar ingredients found in popular energy drinks are far below the amounts expected to deliver therapeutic benefits or adverse events (1).



Energy drinks are heavily marketed, especially to young adults, with slogans such as "Red Bull gives you wings" and others that compare the effects of the drinks to the use of stimulating drugs. In addition, many of these drinks are heavily marketed in bars or for use in combination with alcohol, which could further increase the health risks for consumers. More than half of all college students ingest energy drinks, according to one East Carolina University survey, with most using them to counter insufficient sleep (67%), to increase energy (65%), and to drink with alcohol while partying (54%). Weekly jolt-and-crash episodes were experienced by 29% of users, and 19% reported heart palpitations (3).

Another survey of North Carolina college students showed that one in four mixed alcohol with energy drinks and were at increased risk for alcohol-related consequences (6). Researchers at the University of Buffalo have shown that male frequent users of energy drinks are more prone to "toxic jock identity" or hypermasculinity, risk-taking behavior, alcohol and drug abuse, physical fighting, and unsafe sex (5).

An energy drink lawsuit was filed by the Center for Science in the Public Interest against MillerCoors in regard to its alcoholic energy drink Sparks. The lawsuit alleged that Sparks contained unapproved additives and posed a health risk to consumers. Similar alcoholic energy drinks sold by Anheuser-Busch as Bud Tilt and Bud Extra were removed from the market in June 2008 after a similar lawsuit was filed by state attorney generals and advocacy groups.

One study from the Barrow Neurological Institute in Phoenix linked heavy consumption of energy drinks with seizures in four patients (2). In the wake of several recent deaths linked to energy drinks, a number of countries including France, Turkey, Denmark, Norway, Uruguay, and Iceland have instituted restrictions on their use. Canada requires warning labels cautioning against use by children or pregnant women, use in large quantities, and use with alcohol. Energy drink consumption remains unregulated in the United States, and the U.S. Food and Drug Administration does not currently require energy drinks to display warnings or limit the amount of caffeine they can contain.

One can of Red Bull falls short of the caffeine level found in a similar quantity of coffee, but some energy drinks have caffeine levels far higher, and legislation may be necessary to limit caffeine concentration and provide product information and warning labels. According to researchers at Johns Hopkins University, the labels of popular energy drinks, such as Red Bull and Rockstar, should contain warnings about the amount of caffeine they contain and the potentially harmful side effects they could cause (7). The researchers suggest that most consumers are unaware of the caffeine content in these energy drinks or about the potential dangers, and that information should be added to the product labels. Johns Hopkins scientists and physicians have written a letter to the U.S. Food and Drug Administration asking that energy drinks contain a prominent label listing caffeine content, and that the concentration of caffeine come under regulation.

Caffeine in and of itself has not been related to health risks. Recent large-scale studies have shown that coffee, tea, and caffeine users experience modest decreases in risk of heart disease, Type 2 diabetes, liver cancer, and breast cancer (8). Despite earlier concerns, caffeinated beverages do not cause bone loss.

Among undergraduate students, the frequency of energy drink consumption has been linked to marijuana use, sexual risk taking, fighting, smoking, alcohol problems, and illicit prescription drug use (4). Thus, the real problem with energy drinks is the user who ingests high amounts or combines intake with alcohol abuse and other risky behaviors. Another concern is the style of advertising used by energy drink companies that principally target teens and young adults and promotes the performance-enhancing and stimulant effects of energy drinks with drug-related terms such as blow and cocaine.

In general, a can of Red Bull is not much different than having a cup of coffee with cream and sugar. But mix in some aggressive marketing, alcohol use, and risky behavior, and energy drinks are no longer as benign as a cup of joe.

Back to Top | Article Outline


1. Clauson KA, Shields KM, McQueen CE, Persad N. Safety issues associated with commercially available energy drinks. J Am Pharm Assoc. 2008;48(3):e55-e63.
2. Iyadruai SJ, Chung SS. New-onset seizures in adults: Possible association with consumption of popular energy drinks. Epilepsy Behav. 2007;10(3):504-8.
3. Malinauskas BM, Aeby VG, Overton RF, Carpenter-Aeby T, Barber-Heidal K. A survey of energy drink consumption patterns among college students. Nutr J. 2007;6:35.
4. Miller KE. Energy drinks, race, and problem behaviors among college students. J Adolesc Health. 2008;43(5):490-7.
5. Miller KE. Wired: Energy drinks, jock identity, masculine norms, and risk taking. J Am Coll Health. 2008;56(5):481-9.
6. O'Brien MC, McCoy TP, Rhodes SD, Wagoner A, Wolfson M. Caffeinated cocktails: Energy drink consumption, high-risk drinking, and alcohol-related consequences among college students. Acad Emerg Med. 2008;15(5):453-60.
7. Reissig CJ, Strain EC, Griffiths RR. Caffeinated energy drinks - A growing problem. Drug Alcohol Depend. 2009;99(1-3):1-10.
8. van Dam RM. Coffee consumption and risk of type 2 diabetes, cardiovascular diseases, and cancer. Appl Physiol Nutr Metab. 2008;33(6):1269-83.
© 2009 American College of Sports Medicine.