Clinical TopicsNutrition/SupplementsPatient SafetyWorkplace Management

High-energy drinks: What you don’t know could hurt you


Red Bull. Full Throttle. 5-Hour Energy. RockStar. Monster. AMP. Starbucks DoubleShot. Americans are consuming these and other high-energy drinks in record numbers. Reportedly, these beverages are the fastest-growing segment of the soft-drink market; some are among today’s top-selling drinks. Children (ages 12 and younger), adolescents (ages 12 to 8), and young adults (ages 19 to 25) make up about half the market.

By the end of 2011, sales of these beverages are expected to top $9 billion. The zingy brand names, snappy slogans, snazzy designer cans, and youth-oriented marketing promote their skyrocketing sales, despite the outrageous cost of a single can—more than $2.

But most Americans are consuming them with little thought or understanding of the risks of their consumption—or their abuse potential.

What’s the buzz?

The main ingredients in regular high-energy drinks are large amounts of sugar and caffeine, as well as combinations of nutrients and herbal supplements. These combinations can give the drinker the sensation of a sudden energy rush. One 8.4-oz serving of Red Bull, for instance, contains 80 mg caffeine and 27 mg sugar—tantamount to drinking one 8-oz cup of coffee with seven teaspoons of sugar.

Sugar-free high-energy drinks may contain aspartame, sucralose, or a combination of artificial sweeteners. Aspartame is 180 times sweeter than sugar; nutritionally, it has the same energy value as sugar. So high-energy drinks containing aspartame produce the same sudden rush of energy.

Those that contain sucralose produce the energy-rush sensation through a combination of vitamins, nutrients, and herbal supplements. Sucralose is 600 times sweeter than sugar and 200 times sweeter than aspartame. It’s not used by the body for energy production because the body can’t break it down. So high-energy drinks containing sucralose must produce their energy boost with other substances.

High-energy drink “shots” contain even higher caffeine levels than other high-energy drinks, plus a mixture of herbs, vitamins, and nutrients that when combined, provide that energy rush. Shots are sold in volumes ranging from 0.08 to 3 oz per container. The caffeine in a “shot” may be five times greater than that in a regular 8-oz cola.

Why do people drink them?

People consume high-energy drinks for various reasons—as a quick pick-me-up or mood enhancer, to increase mental alertness, to boost physical energy, or for help staying awake at night. The main reason these drinks are so popular is the energy rush they provide.

What’s in them?

Regular high-energy drinks are essentially nothing but sugared sodas filled with caffeine and empty calories, with no real nutritional value or benefit. (See the box below.) Their high sugar content slows absorption of water into the body, making them unsuitable for rehydration during prolonged and vigorous exercise. Sugar enters the bloodstream quickly and gives a sudden energy burst that can last from several minutes to several hours. Actually, some health experts believe people who consume these drinks end up feeling worn out, not “helped out.” One of the body’s natural defenses is to slow a person down and cause a tired feeling. These drinks prevent the body from carrying out that vital function.

Weighted Checklist


Caffeine is the most widely ingested psychoactive drug in the world. High-caffeine drinks act as a stimulant, producing a brief performance boost. Caffeine stimulates the central nervous system (CNS) by increasing the heart rate and mental alertness. Most caffeine-sensitive people experience a temporary increase in vitality and mood elevation after drinking high-energy beverages.

Other effects of caffeine include cardiac stimulation and coronary vasodilation. Caffeine relaxes smooth muscle, stimulates skeletal muscle, and has a mild diuretic action. Also, it can cause loss of potassium and calcium, which can lead to muscle soreness and delay recovery time after exercise. Caffeine’s diuretic effect and the potassium and calcium loss it causes make high-caffeine drinks poor choices for hydration or replacement of carbohydrates or electrolytes.

Toxic effects of caffeine include vomiting, abdominal pain, agitation, altered state of consciousness, rigidity, and seizures. Large caffeine doses (more than 500 mg daily) can cause anxiety, dizziness, palpitations, headaches, muscle twitching, and GI problems. Chronic consumption of high-caffeine beverages can lead to dependence, tolerance, drug craving and, with abrupt cessation, unpleasant withdrawal symptoms.


Guarana is a South American plant that contains large amounts of caffeine, theobromine (a chronotope), and theophylline (an inotrope). Guarana boosts the caffeine level of high-energy drinks dramatically. One gram of guarana may contain 40 to 80 mg caffeine. Guarana may be listed in the ingredients as part of the “energy blend.”

Herbal supplements

Herbs containing alkaloids have varying effects, from the caffeine buzz you get from coffee and guarana to the more intense effects of ma huang (ephedrine) or the high you get from coca leaves (a form of cocaine). These herbs give you a burst of energy but tend to leave you markedly fatigued once that effect wears off, so you feel more tired than you did before consuming the herb. Unpleasant side effects include a faster heart rate, jitters, clouded thinking, and aggression. These herbs also can cause habituated or addictive behaviors. Examples of alkaloid herbs are kola nut, yerba mate, coca, ma huang, and guarana.

Another herb that reportedly has a stimulant effect is eleuthero (Siberian ginseng)—one of the most popular energy-boosting herbs used today. Eleuthero is purported to increase stamina and immunity and shorten recovery time.

Gotu kola purportedly improves brain function, strengthens tissues and blood vessels, and acts as a rejuvenator and a tonic with anti-inflammatory properties. Maitake, a Chinese mushroom, purportedly stimulates the immune system and helps fight chronic fatigue.


Certain nutrients that may help fight fatigue and provide increased energy may appear on the ingredients list of high-energy drinks at several times their recommended daily allowances (RDAs). For example, sugarfree Red Bull lists niacin at 140%, vitamin B6 at 360%, and vitamin B12 at 120% of their RDAs. B vitamins (especially B12, biotin, and folic acid) are known for their energy-boosting abilities. They may help fight fatigue by aiding the body’s glucose utilization; they also promote red blood cell formation.


A 2-aminoethanesulfonic acid, taurine plays an important role in digestion and promotes GI absorption of lipids. It plays a role in memory function and works in electrically active tissues, such as the brain and heart, to stabilize cell membranes.

Taurine-laced drinks are marketed as performance enhancers that improve memory and overall athletic performance. Studies on the effects of taurine and caffeine (two of the active ingredients in Red Bull, for instance) on short-term memory found mixed results: The taurine-caffeine combination had no effect on short-term memory but caused significant decreases in heart rate and mean arterial pressure.

What are high-energy drink cocktails?

Some people who like to party all night prefer high-energy drink cocktails. These drinks sell well, although health experts have many concerns about them. “Vodka Bulls” and “Yager Bombs” (vodka or Jagermeister mixed with a high-energy drink) are some of today’s more popular drinks in bars. Other popular cocktails are the “Grape Bomb” and “Cherry Bomb” (energy drinks with grape or cherry vodka), the “Starburst” (an energy drink with every flavor of Stoli Vodka), and the “Tic Tac” (an energy drink with rum and orange juice). For some people who drink such cocktails, the type of energy drink or alcohol mixer used doesn’t much matter.

The sugary sweetness of an energy drink masks the taste of alcohol, making it appealing for those who can’t stomach the taste of hard liquor. As a result, they may ingest these cocktails faster than other mixed drinks. Claims related to mixing high-energy drinks with alcohol include increased alertness (which may cause a person to drink more alcohol and party longer), a reduced alcohol effect (making the drinker feel less intoxicated), and faster recovery from a hangover. But little scientific evidence supports these claims.

Do high-energy drinks have benefits?

High-energy drinks can have benefits when consumed in moderation. Studies of their effects on cognitive and physiologic functions show that consuming high-energy drinks with high glucose and caffeine concentrations can improve cognitive performance. One study reported Red Bull significantly increased physical endurance, mental performance, and alertness; however, research subjects quickly developed tolerance. Research on the effects of high-energy drinks on sleepy drivers found these drinks significantly improved drivers’ lane drifting and reaction time for upwards of 2 hours after consumption.

What are the risks?

One significant risk is the increased incidence of dehydration when high-energy drinks are consumed before, during, or just after strenuous activity. Drinks with high caffeine, sugar, and carbohydrate levels can impede rehydration, causing GI distress, a laxative effect, palpitations, and increased diaphoresis. They shouldn’t be consumed when rapid rehydration is needed, such as after strenuous exercise or as a fluid-replacement drink.

Other risks relate to the effects of caffeine and its potentially addictive nature, the poor nutritional value of these drinks, and the dangers of mixing them with alcohol. Mixing these beverages with alcohol is like combining a stimulant with a depressant. Individuals who ingest large amounts of high-energy drinks may not realize how intoxicated they are. The stimulant effect of an energy drink counteracts alcohol’s depressant effect, increasing the risk of alcohol poisoning; caffeine’s diuretic effect combined with that of alcohol may double the risk of dehydration. The combined effect of caffeine and alcohol may cause dehydration to increase faster than when alcohol or caffeine is consumed alone. Also, combining high-energy drinks with alcohol makes intoxicated persons more alert (wide-awake drunkeness), and an alert intoxicated person may be more likely to engage in risky behavior, such as getting behind the wheel of a car.

High-energy drink manufacturers aren’t required to list caffeine content from herbal supplements, so the actual caffeine content in a single 8-oz serving may exceed what’s listed on the container. The Food and Drug Administration has set a 71-mg limit on the amount of caffeine in 12 oz of soda. But high-energy drink manufacturers circumvent this limit by stating their drinks are natural dietary supplements. Safety determinations for high-energy drinks are made by manufacturers; no requirements exist for testing, warning labels, or restrictions on sales or consumption by minors.

Most high-energy drinks now come in a variety of sizes ranging from 8 to 32 oz—yet the ingredients and amounts listed on the label reflect those of an 8-oz single serving size. Be aware that a 16-oz energy drink has two servings, and you need to double all the amounts on the label to determine how much of each ingredient you’re consuming.

Teach patients the facts

As nurses, we’re obligated to educate the public about healthy choices. We need to be aware of the potential dangers of high-energy drinks and teach patients about these dangers and the consequences of inappropriate use. Focus your teaching on the amount and frequency of consumption. Caution patients not to consume high-energy drinks as thirst quenchers (especially if spiked with alcohol) or as sport drinks. Inform them that during times of high physical activity, the best choice for fluid replacement is water or a sports drink containing replacement electrolytes.

For someone who drives long distances at night, feels sleepy or tired during shift work, or needs a quick-pick-me-up, an occasional high-energy drink might be appropriate. But advise patients who consume these beverages to use caution and drink them only in moderation to avoid their inherent dangers.

Debra Neale is chief nursing officer at Bassett Healthcare Network—O’Connor Hospital in Delhi, New York.

Selected references

Arria A, O’Brien M. The “high” risk of energy drinks. JAMA. 2011 Feb;305(6):600-1.

Bichler A, Swenson A, Harris MA. A combination of caffeine and taurine has no effect on short term memory but induces changes in heart rate and mean arterial blood pressure. Amino Acids. 2006 Nov;31(4):471-6.

Energy boost herbs. Accessed July 27, 2011.

Higgins Jp, Tuttle TD, Higgins CL. Energy beverages: content and safety
Mayo Clin Proc. 2010 Nov;85(11):1033-41.

Horne JA, Reyner LA. Beneficial effects of an “energy drink” given to sleepy drivers. Amino Acids, 2001;20(1):83-9.

Laquale K. Red Bull: the other energy drink and its effect on performance. Athletic Therapy Today. 2007;12(2):43-5.

Marczinski CA, Fillmore MT. Clubgoers and their trendy cocktails: Implications of mixing caffeine into alcohol on information processing and subjective reports of intoxication. Exp Clin Psychopharmacol. 2006 Nov;14(4):450-8.

Mayo Clinic Staff. Caffeine: How much is too much? March 9, 2011. Accessed July 12, 2011.

Oteri A, Salvo F, Caputi AP, Calapai G. Intake of energy drinks in association with alcoholic beverages in a cohort of students of the School of Medicine of the University of Messina. Alcoholism Clin Exp Res. 2007 Oct;31(10):1677-80.

Pennay A, Lubman DI, Miller P. Combining energy drinks and alcohol—a recipe for trouble? Aust Fam Physician. 2011 Mar;40(3): 04-7.

Seifert S, Schaechter J, Hershorin E, Lipshultz S. Health effects of energy drinks on Children, adolescents, and young adults. Pediatric.s 2011 Mar;127(3):511-26.

Smit H, Cotton J, Hughes S, Rogers P. Mood and cognitive performance effects of “energy” drink constituents: caffeine, glucose, and carbonation. Nutr Neurosci. 2004 Jun;7(3):127-39.

Wong M. Herbs for energy. eHow Health Topics A to Z. Accessed July 27, 2011.


  • Martha Sparkman
    December 25, 2021 9:05 pm

    You mentioned ‘cocoa leaves’ in your article. The leaves of the cocoa tree are not similar to coca leaves.
    One creates photosynthesis for the source of the food called ‘chocolate’.
    The other is a plant with psychoactive effects, which is used to make legal and illicit drugs.
    Please correct the spelling.

    March 18, 2014 12:02 pm

    There’s 88 mg of caffeine in 8.4 oz. Of Red Bull.

  • This is a research article on the cellular effects of energy shots. Particularly striking are the pictures of how long it takes wounds exposed to these substances to heal (toward the end). Check it out:

  • I used to drink energy drinks all the time. No longer will I drink them after reading this article, thanks for the helpful info.

  • Great educational material especially for the young ones & also for all of us.

  • excellent article thank you

  • I am very impress with the information that was pesented. I always knew that these high engery drinks contained large quantities of caffine and sugar, but the herbal ingredients was a shocker for me. These drinks are are eye openers in moderation but deadly when abused. I know of health providers who use it daily in the emergency room. I will definitely pass it on to them as well as the patients in the community (Peds E.R.). Thanks again for a wonderful article.

  • Excellent article. A very unique topic and a very well balanced perspective. I used my MacBook Pro computer “Speech” program to listen to it being read to me and it was very informative and an enjoyable way to become educated on such a massive market place item that, i feel we as RN’s may well be overlooking – many even misusing and frequently consuming to get thru the 12-16 hour shifts. Very good job. Thank you Debra Neale. Steven J Fields RN.

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