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Energy Drinks: What Teenagers, Doctors, and Parents Should Know

Top-selling energy drinks contain high, unregulated amounts of caffeine, as well as other stimulants which can enhance the effects of caffeine and produce harmful health effects in adolescents, warns a new article in the journal Pediatrics in Review.1

Energy drinks

Reviewing current information about the content, benefits, and risks of the use of energy drinks by teens, Navy, Army and Air Force doctors expressed "great concern" over the safety and negative effects of energy drinks, given their high caffeine content and the common practice on college campuses (and most likely at the high school level as well) of mixing energy drinks with alcohol. 

Marketed to adolescents 

Introduced in the late 1980's, the energy drink market has since grown to a $5 billion a year industry, with more than 200 brands introduced into the United States in 2006. Growth has been achieved largely by marketing primarily to adolescents, particularly males, with one market research study finding that teens increased their energy drink consumption by 16% from 2003 to 2008, with 35% of teenagers regularly consumers.  

Energy drink manufacturers allocate a significant share of marketing resources to sports sponsorships, including soccer teams (e.g. New York Red Bulls), automobile racing teams, and extreme sport athletes.  Not surprisingly, the result has been that a survey of almost 800 college students found that 39% drank energy drinks in the past month (males more than females), and that "jock identity" was linked to frequency of energy drink (and energy drink mixed with alcohol) consumption.

Energy drink ingredients

According to the study, most energy drinks contain the same basic ingredients:

  • Caffeine: Rarely listed as an official ingredient, but found in all of the top-selling energy drinks at levels ranging from 154 mg. to 280 mg. per can, amounts much higher than contained in a cup of coffee (80 to 120 mg.) or tea (50 mg.), or a 12-ounce can of cola (which cannot by law contain more than 65 mg. of caffeine).  While there is no recommended daily allowance for caffeine, the American Dietetic Association says that women of reproductive age and children should consume no more than 300 mg of caffeine per day.  
    • Caffeine has been linked to a variety of health effects, including irritability, anxiety, mental confusion, hand and limb tremor, osteoporosis, digestive problems, nausea, insomnia and sleepiness, urinary frequency, headache, palpitations, cardiac arrhythmias, and elevated blood pressure.  
    • Withdrawal symptoms have been reported in school-age children who drank as little as 120 to 145 mg per day (one to two cups of coffee or three to five sodas) over a 2-week period.
    • Cardiovascular effects as a result of heavy caffeine use can lead to death in athletes. The diuretic effect of high levels of caffeine could lead to dehydration in athletes who do not drink enough fluids to compensate.
    • While caffeine was removed by the World Anti-Doping Agency (WADA) from its list of banned substances in 2004, it is reconsidering its ban.  Caffeine is considered illegal by the NCAA if found in quantities in urine that approximate 5 to 8 cups of coffee consumed in hour; depending on the brand, that is as few as one to three energy drinks.
    • Studies of depressed youth show that they use more caffeine than nondepressed youth, and caffeine likely exacerbates daily anxiety.  Daily caffeine use was associated in another study with clinical dependence, even among those who only drank two to three cups of coffee daily. The same study found that adolescents who met criteria for marijuana or other drug dependence consumed significantly more caffeine than those not dependent on marijuana or other drugs. 
    • A survey of over 5,000 7th graders showed that those at high caffeine risk (ie, consuming more than six cups of coffee in the previous month) were more likely to use tobacco or alcohol at 1-year follow-up.
    • Energy drinks mixed with alcohol present serious potential for harm and abuse. With such use, the intensity of response diminishes, leading to tolerance so that higher doses of alcohol may be needed to attain the initial effect, "planting the seeds of abuse and dependence," say the study's authors.
  • Guarana. Also known as Brazilian cocoa, it contains a substance called guaranine, which is caffeine. 1 gram of guarana is equivalent to as much as 40 mg of caffeine. If an energy drink discloses the caffeine content at all, it usually does not take into account the guarana, which has been reported to exert a more prolonged effect than an equivalent amount of caffeine. Guarana has not been evaluated by the FDA for safety, efficacy, or purity, and the potential risks and benefits may not be known.
  • Sugars. Most energy drinks contain sugars in the form of sucrose, glucose, or high fructose corn syrup, with a sugar content varying from 21 to 34 g per 8 ounce serving, an amount similar to that found in sodas and fruit drinks. Drinking two to three energy drinks could be consuming 120 to 180 mg of sugar, an amount 4 to 6 times the maximum daily intake under USDA dietary guidelines. According to some studies of adults, the glucose and caffeine can work synergistically to enhance athletic and cognitive performance. Teens who consume a lot of energy drinks may be at risk for obesity and dental health problems. 
  • Taurine: One of the most common ingredients in energy drinks, taurine is present in meat, seafood, and milk, and one of the most abundant amino acids in the human body, which can manufacture taurine on its own from other amino acids. It is purported to have beneficial physiologic effects but those effects cannot solely be attributed to taurine, because it is mixed with caffeine and other substances. The amount of taurine consumed by regular consumption of energy drinks far exceeds the amount in a normal diet (40-400 mg/day). Although there is limited evidence of adverse health effects from taurine use, some animal studies suggest that it might minimize some of the adverse effects of alcohol consumption, encouraging greater such consumption.
  • Ginseng: A root most commonly found in East Asia, ginseng has been claimed to improve athletic performance (although there is little scientific evidence to support such claims), stimulate the immune system, and improve mood, but has been linked to insomnia, headache, vertigo, mania, and estrogen-like effects, such as breast tenderness and amenorrhea (cessation of menstrual cycle). Many energy drinks do not contain ginseng in amounts considered therapeutic (100-200 mg/day), requiring the user to drink two to four cans of an energy drink to obtain even the lowest therapeutic dose.  
  • Other additives: Energy drinks often contain a variety of other additives that purport to have a "bevy" of positive effects. Most of the claims about these ingredients lack sufficient scientific basis, and are either in doses so low or so high that no one knows what effect they have on the human body.  Even taking into account some of the known physiologic benefits, little is known about the effects of daily energy drink consumption on long-term health.
  • Alcohol: One-fourth of college students recently surveyed at ten universities in North Carolina had consumed energy drinks mixed with alcohol in the past month. They were more likely to be younger, white, mail, engaged in athletics, or members of fraternities or sororities, and at significantly higher risk of alcohol-related consequences from consumption, including: Being taken advantage of sexually, taking advantage of another sexually, riding in a car with a driver under the influence of alcohol, being hurt or injured, or requiring medical treatment.  Adolescents who combine energy drinks with alcohol perceive less of an effect from alcohol but are still impaired in terms of motor coordination and visual reaction time. Thus, there is the "grave danger that adolescents may feel unimpaired, when they are just as impaired as a person with the same blood alcohol level, and subsequently drink much more than they intended to and attempt to drive themselves and others home.  The sobering reality, says one school official, is that they are a "wide-awake drunk."

Clinical intervention

The authors recommend that primary care physicians:

  • Conduct a so-called HEEADSSS interview (Home, Education, Eating, Activities, Drugs/Alcohol abuse, Sexual activity, Safety, Suicide/Depression), which is a perfect time to ask about energy drink use, assess risk-taking behaviors, and provide counseling: under the D, students should be asked about drug use, caffeine intake, and energy drinks, alcohol use, segueing into specific questions on alcohol mixed with energy drinks.  An opportunity to educate teens may present itself; many teens may have no idea how much alcohol and caffeine they are consuming when they ingest energy drinks.
  • Add questions about energy drinks with alcohol to the series of six questions (CRAFFT) developed to screen teens for high-risk alcohol and other drug use disorders : (1) Have you ever ridden in a CAR driven by yourself or someone who had been using alcohol or drugs? (2) Do you ever use alcohol/drugs to RELAX, feel better about yourself, or fit in? (3) Do you ever use alcohol/drugs while you are ALONE?  (4) Do you ever FORGET things you did while using alcohol/drugs? (5) Do your family or FRIENDS ever tell you that you should cut down on your drinking/drug use?  (6) Have you ever gotten into TROUBLE while you were using alcohol/drugs?


Parents should ask that their child's pediatrician discuss energy drink consumption with their teen, including the therapeutic benefit and the significant risks, which may outweigh the benefits in the adolescent consumer. Parents and adolescents need to be educated about the potentially dangerous consequences of energy drink consumption. 

1. Blankson KL, Thompson AM, Ahrendt DM, Patrick V.  Pediatrics in Review 2013;34(2):55-62. 

Posted February 4, 2013