Concerns about energy drinks have been gathering pace, with some groups, particularly in the US and the UK, now calling for them to be more tightly regulated and for greater public awareness of what they contain, their potential side-effects and risk of addiction.

Although their history dates back to the early 1900s, energy drinks started coming into vogue in the 1970s and 1980s as performance-enhancing products sought by young people who wanted to prolong their enjoyment of physical activities.

In the US, Gatorade was probably one of the first performance-enhancing drinks to be manufactured as such: it was originally produced by a team of researchers at the University of Florida in the 1960s in response to a request from the Gators football coach who was fed up with his team’s performance during practices. The first Gatorade thirst-quenching formula included water, sodium, sugar, phosphate, lemon juice and potassium.

In the UK, it was Lucozade that came to prominence: a beverage originally introduced in 1929 as a hospital drink for aiding recovery. In In 1938, Beecham (now GlaxoSmithKline) acquired Lucozade from its inventor W.W. Hunter, to enter the “health-drink field”, and by the early 1980s Lucozade was being promoted as a drink to “replenish” lost energy.

However, since then, public perception and consumption of energy drinks appears to have shifted from dietary supplementation to recreational use, and some might now even say, recreational abuse, with the latter perhaps boosted by the arrival of alcoholic energy drinks, the dangers of which have been illustrated with the recent hospitalization of nine US students aged 17 to 19, allegedly for consuming too much Four Loko, an alcoholic energy drink that is colloquially referred to as “blackout in a can” or “liquid cocaine”.

Energy drinks are “soft” drinks (that is non-alcoholic beverages) marketed as “energy boosters”, but even under this definition, there is confusion, because often, the marketing that accompanies these drinks does not dwell on the sugars they contain (which is where energy comes from), but stresses other ingredients such as stimulants, vitamins and herbal extracts.

The confusion around the expression “energy drink” has now escalated to a nonsensical level, with the arrival of products like Impulse Energy’s Extreme brand, marketed as a “sugar-free energy drink”; while an even more peculiar contradiction in terms is the phrase “zero-carb, zero-calorie” energy drink, used to describe Impulse Zero: literally an energy drink that delivers no energy.

So, if energy drinks aren’t necessarily supplying us with energy, what is their appeal? The answer is, caffeine. And that is where the concern arises, for caffeine in excess, particularly for young people consuming too much too soon, can lead to some unpleasant, and dangerous symptoms.

Consider the story of “Amy”, whose first and she says now last, experience with energy drinks, was posted recently on the website of Think Before You Drink, a watchdog organization.

Amy tells of when she finished high school and was asked to make the Valedictorian graduation speech. She spent weeks preparing the speech, and because she could not sleep the night before the big day, she felt “groggy” the next morning.

As the moment to deliver the speech drew nearer, she felt her brain become “completely scattered”. So she went to the vending machine and bought three cans of energy drinks and drank them all. She said she felt “great”, like “a light bulb turned on in my brain”, as she stepped up to the podium. She remembers greeting all her classmates, but then … the next thing she knew she woke up in hospital.

“Apparently I crashed hard, fainted, and ended up urinating myself,” she wrote. She added that she has never “lived this down”, and can’t drink caffeine ever again. She asked the website owners to “share my story with your community”.

What happened to “Amy”, was not surprising. Adults who drink tea and coffee regularly gradually build up a tolerance, but for young people, the risk of caffeine intoxication, especially if they have no tolerance, and drink too much too soon, is much higher.

Caffeine is a compound that is naturally present in the leaves and seeds of many plants. Man-made forms are also added to foods. In its natural state it tastes very bitter.

Caffeine stimulates the central nervous system and makes us feel alert, gives us a temporary energy boost and improves mood. It is not stored in the body but its effects can last for up to 6 hours.

It is present in chocolate, coffee, tea and many soft drinks. It is also present in pain-relievers and over the counter medications.

Caffeine intoxication is a clinical syndrome that is accepted by authorities such as the Diagnostic and Statistical Manual of Mental (DSM) Disorders and the World Health Organization’s International Classification of Diseases (ICD). They say that caffeine intoxication can lead to nervousness, anxiety, restlessness, pacing (psychomotor agitation), insomnia, stomach upset, tremors, rapid heartbeat, and in rare cases, even death.

In October 2008, one hundred scientists and doctors became so concerned they signed a letter to the US Food and Drug Administration (FDA), asking for regulation on energy drinks to be tightened up because their high caffeine content puts younger drinkers at risk of being intoxicated with caffeine.

The letter was written by Dr Roland Griffiths, a neuroscientist at Johns Hopkins School of Medicine in Baltimore, who with his colleagues had just published a paper in the journal Drug and Alcohol Dependence, calling for clear labelling of energy drinks to show the amount of caffeine they contain.

Griffiths said the caffeine content of energy drinks varies over a “ten-fold range”: it is possible to buy a can of energy drink with the same amount of caffeine as 14 cans of Coca-Cola, and not realize this because there is no label showing how much caffeine it contains, and few include warnings about the possible health risks of caffeine intoxication.

He and his colleagues reviewed caffeine levels in energy drinks widely sold in the US and found they varied from 50 mg of caffeine in a can of “Whoop Ass”, to 505 mg in another called “Wired X505”. For comparison, a standard 12-oz can of cola has about 35 mg of caffeine and a 6-oz cup of brewed coffee has between 80 and 150 mg.

They also pointed out that since energy drinks are marketed in the US as “dietary supplements”, they don’t have to obey the FDA limit on the caffeine content of soft drinks, which is 71 mg for a 12-oz can, and they highlighted the curious inconsistency that exists where over the counter products containing caffeine have to carry warning labels while energy drinks do not.

Griffiths told the press that since energy drinks first arrived, there has been a “sea change” in how they are being marketed.

He said the FDA should require manufacturers to put warning labels on their energy drink cans, list their caffeine content on the cans, and limit the amount of stimulant they contain.

Also in the UK, concern is growing about the amount of energy drinks being consumed by young people, including schoolchildren.

Drug Education UK delivers drug awareness classes in schools. Their drug expert Bob Tait told a nursing conference reported by Nursing Standard magazine in September 2008 that they were becoming increasingly concerned about the growing problem of schoolchildren consuming energy drinks, which they say is causing them to become hyperactive and disruptive in class.

Tait said drinking too many energy drinks can lead to caffeine intoxication and cause chest pains and headaches and asked that school nurses keep a lookout for such problems in schools.

He said as he goes round schools giving talks to children he asks them who is drinking energy drinks like Red Bull and they put their hands up. He said there was one boy who was drinking eight cans a day, “that is too much”, he added.

One can of Red Bull energy drink has the same amount of caffeine as a cup of coffee.

According to the manufacturer’s information, Red Bull energy drink has been developed “for times of increased mental and physical exertion”. They say their drink increases “performance, concentration and reaction speed”, improves “vigilance and emotional status,” and “stimulates metabolism”. A spokesperson for the company told the BBC when they reported Tait’s comments that their energy drink was not aimed at children.

But Tait, who describes energy drinks as “fashionable”, said part of the problem is that parents give the drinks to their kids, but he also blamed shopkeepers.

There is also a worry that young people will fall foul of the “gateway” effect: where becoming addicted to energy drinks could make it more likely that they will move onto riskier substances. Marijuana, for example, has been termed a gateway drug because it has been linked to the increased use of alcohol and drugs.

Dr Conrad Woolsey, Assistant Professor of Health and Human Performance at Oklahoma State University and a sport psychology consultant, talked earlier this year at a conference about his research on college students that suggests energy drinks could be the “next gateway drug”.

He told delegates at the American Alliance for Health, Physical Education Recreation and Dance (AAHPERD) conference in Indianapolis in March, that studies he and his colleagues carried out involving 700 students indicated that energy drink users “consumed more than double the amount of alcohol and had far riskier drinking habits than those who drank alcohol only”. They also found that energy drink users were significantly more likely to practise risky behaviours such as drinking and driving and using amphetamines.

Woolsey, whose research expertise includes brain chemistry, addiction and health behavior change, said that stimulants in energy drinks (for example guarana, ginseng, yohimbine HCL, evodiamine, yerba-mate, N-Acetyl-L-Tyrosine, and others) have similar effects on the brain’s neurotransmitters dopamine, serotonin and epinephrine, as other drugs of abuse, and that adolescents and young adults are more vulnerable to addictions because their memory and reward centers in the brain are underdeveloped.

He said it “makes sense for alcohol and energy drink advertising campaigns to target populations who are vulnerable to coercion and more likely to become long term users of their products”, and as an example of this described how companies give students on campus free samples of energy drinks during athletic events and times of “increased academic stress“, and then once they are “hooked”, take advantage of their products’ addictive properties and start charging high prices (2 to 4 dollars a can).

Woolsey suggests that such aggressive marketing is how sales of energy drinks in North America have shot up from 200 million dollars in 2002, to 3.5 billion in 2006 and 4.7 billion in 2007.

In the UK, the Food Standards Agency advises pregnant women to consume no more than 200 mg of caffeine a day, which according to their own advice is about 2 mugs of instant coffee, about 1.4 mugs of filter coffee, nearly 3 mugs of tea, and about 2.5 cans of “energy drink”.

They state their reason as high levels of caffeine can cause miscarriage, and result in babies having a lower birthweight, which increases their risk of developing health problems.

Another emerging concern is the “alcoholic energy drink”, which has a strong alcohol and caffeine content and appear in cans similar to non-alcoholic energy drinks. In November 2009, the FDA sent letters to nearly 30 manufacturers of these drinks demanding that they produce evidence that their “caffeinated alcoholic beverage” products were safe and wrote they would take regulatory action, including product seizures, if their information did not show adequate proof of safety.

There has been no public announcement of what the FDA has done since their letter to the manufacturers, which has prompted a group of Senators to write to the FDA calling on them to make public their findings from their investigations into the possible health risks of alcoholic energy drinks.

According to a news item from alcohol industry watchdog The Marin Institute, the senators also say that alcoholic energy drinks appear to be marketed to underage teenagers, and the labels and containers are so similar to non-alcoholic energy drinks, that they mislead parents and law enforcers.

The problem of alcoholic energy drinks has been highlighted by reports last month that nine students from Central Washington University (CWU) were hospitalized after attending a party in Roslyn where about 50 people had been drinking.

Chief of CWU Police Department, Steve Rittereiser, told the press that their investigation showed that every one of the hospitalized students had drunk Four Loko, an alcoholic energy drink that contains 12 per cent alcohol plus the equivalent of two shots of espresso.

Thus a 23-ounce can of Four Loko contains the same amount of alcohol as about six beers and as much caffeine as in five regular cups of coffee.

The nine students, six women and three men, were freshmen aged between 17 and 19 years and were inexperienced drinkers, reported the Money Times.

Public health officials in the US are concerned that the increasing popularity of caffeinated alcoholic drinks like Four Loko among college students is increasing their risk of cardiovascular damage, and that it is also increasing their personal safety risk because the stimulant effect of the caffeine makes them think they are not as drunk as they really are.

Washington State and New Mexico have now proposed legislation to ban the sale of alcoholic energy drinks.

For concerned parents, and others who would like to be kept informed of what goes into our food and drink, especially if it contains substances that could be harmful when taken in excess, it does not seem unreasonable to ask for content information to appear on the packaging.

Then we can all make up our own minds and take responsibility for our own consumption and its effects on our health.

Sources: USA Today, Marin Institute,,, MNT archives, BBC News, Money Times, AAHPERD Abstracts (March 2010), Guardian, wikipedia, FSA.

Note: this article was amended 2 Nov 10 to take out an uncorroborated reference to comments reportedly made by former Surgeon General of the United States, David Satcher on the potential “gateway” effect and to insert the notes on Conrad Woolsey’s research.

Written by: Catharine Paddock, PhD