Americans guzzled a mind-blowing 3.5 billion energy drinks in 2013, with sales totaling $8.7 billion (Miller A, Dairy Foods 2014;115(3):22).

Red Bull, the brand that basically created the industry, commands a 39% market share, trailed closely by Monster. The market is now so large that business analysts segment it into energy drinks versus energy shots, the latter being small-volume concoctions such as 5-hour ENERGY.

But what, exactly, are energy drinks? Do they actually give you energy? And are they safe?

Brief History

Red Bull was created in the 1980s by an Austrian named Dietrich Mateschitz. Mateschitz was reportedly inspired after trying an Asian beverage called KratingDaeng (which means “red bull” in Thai) and finding that it relieved his jet lag.

He reformulated the product and introduced it in Austria in 1987. Red Bull began entering foreign markets in 1992 and reached the United Stated by way of California in 1997 (Ingram F, Red Bull GmbH. In: Grant T & Ferrara MH, eds. International Directory of Company Histories, Vol. 60. Detroit: St. James Press;2004:252–254).

Currently, Red Bull has sold 40 billion cans since the company’s inception and now has about 10,000 employees in 165 countries (http://bit.ly/1wgymMt).

What’s In the Can?

A can of Red Bull lists 15 ingredients, including carbonated water, caffeine and taurine (the putative active ingredients), two sugars (sucrose and glucose), and a number of B vitamins.

A standard 8.4-ounce can contains 110 calories and 80 mg of caffeine. By way of comparison, a “short” Starbucks coffee contains 180 mg of caffeine, according to the website www.caffeineinformer.com. Caffeine is clearly an effective stimulant, although drinking half of a small Starbucks coffee doesn’t in itself give most people an energy rush.

According to Red Bull’s website, each can contains one gram of taurine, which, according to Natural Standard, an evidence-based resource on integrative therapies, is a “nonessential amino acid-like compound.” It was first discovered in ox bile and was thus named for taurus, which means bull in Latin.

Taurine is involved in several metabolic processes in various body tissues, including the brain and heart, and may have some antioxidant and detoxifying properties. However, it’s not clear that taurine supplements boost energy. Natural Standard gives Taurine a “C” rating for energy, cognitive performance, and exercise performance, where C means there is “unclear or conflicting scientific evidence.”

Does Red Bull enhance performance?

Regardless of the lack of clarity regarding the effects of its individual ingredients, the bottom line is whether Red Bull works. There is actually some science to guide us here.

Driving Performance

Overall, studies have shown that drinking Red Bull improves driving performance. In one investigation, 12 healthy volunteers were randomized to 8.4 ounces of Red Bull, an equivalent amount of sparkling water (placebo), or no beverage (Yamakoshi T et al, Springerplus 2013;2(1):215). Orange juice was added to both the Red Bull and placebo to maintain blinding. Study subjects were then placed in a driving simulator and subjected to 90 minutes of monotonous driving. Each subject completed all three experimental conditions with two- or three-day rest periods between tests.

Subjective sleepiness increased substantially for all three conditions during the driving task with no statistically significant differences between Red Bull and the controls. Driving performance was measured objectively with electronic sensors, and while performance deteriorated for all subjects over time, it deteriorated significantly less for the Red Bull condition.

These results extended prior studies dealing with sleep-deprived drivers that found significantly less “lane drifting,” less subjective sleepiness, and slightly faster reaction times in study subjects who drank Red Bull compared to placebo (Horne JA & Reyner LA, Amino Acids 2001;20(1):83–89; Reyner LA & Horne JA, Physiol Behav 2002;75(3):331–335). The authors, who previously studied caffeine using an identical experimental protocol, observed that Red Bull “is much more effective than coffee with the same amount of caffeine.”

Athletic Performance

Studies testing the effects of Red Bull on athletic performance have been mixed. In one investigation, semiprofessional soccer players consumed about 2.5 cans of Red Bull or a placebo beverage and were then monitored with high-tech electronics (Del Coso J et al, PLoS One 2012;7(2):e31380). Those treated with Red Bull covered more distance during a soccer game—an average of 430 meters (0.27 miles)—and spent more time running and sprinting and less time walking compared to controls.

However, other studies have yielded conflicting results. As an example, Red Bull improved the ability to lift weights in one investigation (Forbes SC et al, Int J Sport Exerc Metab 2007;17(5):433–444) but could not be replicated by others (Eckerson JM et al, J Strength Cond Res 2013;27(8):2248–2254).

Is It Safe?

Red Bull increases blood pressure, heart rate, respiratory rate, and cardiac output in healthy subjects (Grasser EK et al, Eur J Nut 2014;Epub ahead of print). It also decreases blood flow velocity in the brain. This led investigators to conclude that, “one can of [Red Bull] could aggravate pre-existing health problems and warrants further studies using appropriate patient groups.”

But one expert, testifying at a public hearing convened by the Institute of Medicine, noted that someone would have to drink gallons of Red Bull to risk toxicity (Roehr B, BMJ 2013;347:f6343). For a child, the number is about 28 cans, jumping to 93 for an adult.

This seems to comport with field data. Of 2.4 million calls to the National Poison Data System during a one-year span from October 1, 2010, to September 30, 2011, only 4,854 (0.2%) were related to energy drinks (Seifert SM et al, Clin Toxicol (Phila) 2013;51(7):566–574). Drinks classified by investigators as “caffeine-only” beverages such as Red Bull accounted for 946 of those calls. In only six cases, was there a “major effect,” defined as “life-threatening signs or symptoms or marked residual disability.” The majority of these events were seizures and cardiac arrhythmias.

CATR’s Take: Red Bull probably improves performance of certain tasks such as driving. It’s unclear whether this is due to its caffeine content alone, or other ingredients such as taurine. When used in moderate amounts—maybe a can or two per day—Red Bull is likely safe, given the very small number of major poisonings reported in the literature.