What's the buzz with energy drinks?

Published in Health News and Evidence

Date published: About this date

Clinical content may change after this date. This information is not intended as a substitute for medical advice from a qualified health professional. Health professionals should rely on their own expertise and enquiries when providing medical advice or treatment.

Practice points | Energy drinks: what are they, and should we be worried? | The problem with caffeine | Other consequences of energy drink consumption | Information for patients | References


Energy drinks claim to improve performance by delivering a shot of caffeine, sugar and other substances with implied benefit, such as guarana and ginseng. There is very little evidence of clinical, nutritional or therapeutic benefit to consuming these drinks.

In small amounts, energy drinks are probably no more harmful than other caffeinated drinks. However, caffeine toxicity can occur when consumed in large amounts. Risk of toxicity is increased when energy drinks are mixed with other stimulants. Some studies have linked energy drink consumption with increased anxiety, high alcohol consumption, smoking and illicit drug taking.

The TGA has recently issued a safety warning about combining energy drinks and other products containing caffeine with products containing oxedrine. Oxedrine-containing products have been marketed as recreational stimulants and consuming these with energy drinks could potentially cause serious adverse effects. This is particularly relevant as end-of-school-year celebrations approach.

Educate young people about the safe consumption of energy drinks and other stimulants, especially as marketing for these products is specifically targeted at young people.

Practice points

  • Energy drinks have high energy and caffeine content with no nutritional benefit
    There is no evidence that consuming energy drinks will improve performance.
  • High caffeine content has been associated with toxicity and anxiety
    If a young person is concerned about anxiety or is having problems sleeping ask about their intake of energy drinks.
  • Combining energy drinks with products containing oxedrine may be harmful
    Advise parents and young people of the potential dangers of combining caffeine with oxedrine or other stimulants.1
  • Energy drinks are not suitable for children
    Advise parents that water is the most suitable drink for children.2

Energy drinks: what are they, and should we be worried?

The drinks section in supermarkets, service stations or convenience stores display a large variety of caffeinated, high energy drinks. In 2010 New Zealanders and Australians drank 155.6 million litres of energy drinks.3 These drinks now comprise 23% of the total convenience store market3,4 and are a multi-million dollar industry.3 The Department of  Health and the food standards agency (FSANZ) are currently investigating the regulation of energy drinks amid concerns of over-consumption by young people leading to toxicity and other health issues.3,5

Advertising: targeting the young with promises of performance

Energy drink advertising and marketing are targeted at the youth market and half their customers are under 25 years old.6 Many are marketed with claims of improving performance, endurance and mental concentration.7 Marketing slogans and advertising are used to attract consumers who may believe that ‘more is better’ and consume multiple servings.7 None of the claims for improving performance has been substantiated clinically; instead there is evidence for no net benefit to consuming large amounts of caffeine.7

A serious health risk?

Media reports have implicated energy drinks as a serious health risk to those who consume them in excess.5,8 There has been one report of a cardiac arrest thought to have been due to overconsumption of energy drinks combined with strenuous physical activity – in a healthy 28-year-old Australian man.9 A recent media story suggested that a third of all teenagers may be consuming “the equivalent of 10 instant coffees a day in energy drinks”, a number extrapolated from an unpublished survey of teenagers attending a Sydney sleep clinic.10

Reports of overindulgence by young people may make good copy for news reports but what is the actual risk? A recent study found that the incidence of caffeine-related toxicity from overconsumption of energy drinks in Australia increased between 2004 and 2010 with 297 calls regarding exposure to energy drinks taken by the New South Wales Poisons Information Centre (NSW PIC) during this period.4 Most of those affected were male adolescents (57%; median age 17 years) and the number of drinks consumed per session varied widely with a median of 5 units, but ranging up to 80. The most commonly reported symptoms were palpitations, tremor, shaking, agitation and gastrointestinal upset and almost 45% of people calling required treatment in the emergency department. But, to place this in perspective, the NSW PIC fields around 9000 calls per month and over 100,000 calls annually. So although reports of toxicity related to energy drink consumption is concerning, the overall number is low.11

Other associations with energy drink consumption

While the incidence of caffeine toxicity due to energy drink consumption is relatively low, there are other causes for concern. Australian research has shown associations between energy drink consumption and anxiety12 and with higher alcohol consumption, smoking and illicit drug use.13 Both studies were performed in the Western Australian Pregnancy Cohort (Raine) Study which comprises young adults (mean age 20±0.5 years). It is important to note that although these studies both show a correlated effect, it is unclear whether they reflect a cause and effect relationship.

The problem with caffeine

The high caffeine content in energy drinks is of particular concern for children and young adults who generally do not have the experience or tolerance for consuming caffeine in high amounts.7 In healthy adults a daily dose of ≤ 400 mg is considered safe. Acute clinical toxicity begins at 1 g, while a dose of 5–10 g can be lethal.6 For children, caffeine intake should not exceed 100 mg per day and adolescents should not be consuming more than 2.5 mg/kg/day.6 For context, a 500 mL can of a typical energy drink delivers a dose of 160 mg of caffeine.4 A 70 kg adolescent male would only need to consume around 2 cans to exceed this daily limit.

Caffeine is absorbed by all tissues in the body and is structurally similar to adenosine.14 The effects of caffeine on various organ systems include increased heart rate, blood pressure, speech rate, diuresis and temperature.14 Because of the potentially harmful effects, discourage caffeine intake in all children.2,14

Caffeine and alcohol

In the Australian study of calls to the NSW PIC nearly half the callers had also ingested other substances, the most common being alcohol.4 There is some evidence that combined energy drink and alcohol consumption may be problematic as the energy drink appears to mask the individual’s perception of how alcohol-impaired they are, which may lead to greater consumption.2,7 There are also reports that people who consume alcohol mixed with energy drinks are more likely to experience alcohol-related injuries or other alcohol-related consequences.7

Caffeine and herbal stimulants such as oxedrine

The TGA has raised concerns about products containing caffeine with oxedrine.1 Oxedrine is a herbal alkaloid stimulant found in the fruit of Citrus aurantium (also known as bitter orange). Both caffeine and oxedrine are found in a number of health products in Australia which are marketed for a variety of purposes such as appetite suppressants, energy supplements, weight loss aids and recreational stimulants. There have been reports in Australia of adverse events associated with the combined use of caffeine and oxedrine1 and consumption of these products with other caffeine-containing products could pose a serious health risk.1 Patients with pre-existing cardiovascular conditions may be at risk of serious adverse events including arrythmia, tachycardia and cardiac arrest.1

For more information go to the TGA website.

Other additive concerns

While caffeine is the main culprit in toxicity from over-consumption of energy drinks, these drinks may also contain additives that are additional sources of caffeine such as guaranaA or substances such as ginseng (a herbal stimulant) or taurine (an amino acid).4 The amount of these additives in drinks is not thought to be harmful, however, ginseng in particular has interactions with a number of medicines.4

A Food standards code 2.6.4 requires that the total amount of caffeine from synthetic and natural sources is listed on the beverage ingredients list.15

Other consequences of energy drink consumption


Many energy drinks have a high sugar content and over-consumption leads to excessive caloric intake increasing the risk of excess weight and obesity in young people.2,14

Dental erosion

There is potential for consumption of high energy drinks, like sugary carbonated drinks, to promote dental erosion. Most of these drinks are acidic and this is associated with enamel demineralisation.2,14

Information for patients

Young people may not be aware of the risks of excessive energy drink consumption.

  • Help young patients make informed dietary choices by counselling about the caffeine and sugar content of energy drinks.
  • Advise parents to discuss with their teenagers the risks of mixing energy drinks with herbal supplements, especially those containing oxedrine.
  • Advise parents and young patients about the potential dangers of combining caffeine with oxedrine, or other stimulants, and advise them to carefully read the labels of all products and foods including those marketed as energy supplements.
  • Inform parents and young patients that they can get additional information and support from resources such as the NPS Medicines Line 1300 MEDICINE (1300 633 424) or the NSW Poisons Information Centre (13 11 26).
  1. Therapeutic Goods Administration. Caffeine and oxedrine containing products. 2013. [Online] (accessed 18 October 2013).
  2. National Health and Medical Research Council. Australian Dietary Guidelines. Canberra: 2013. [Online] (accessed 26 September 2013).
  3. Food Regulation Standing Committee Caffeine working group. Food regulatory policy options paper. 2013. [Online] (accessed 2 October 2013).
  4. Gunja N, Brown JA. Energy drinks: health risks and toxicity. Med J Aust 2012;196:46–9. [PubMed]
  5. ABC News. Federal Government calls for input on regulation of caffeinated energy drinks amid health concerns. 2013. [Online] (accessed 24 September 2013).
  6. Seifert SM, Schaechter JL, Hershorin ER, et al. Health effects of energy drinks on children, adolescents, and young adults. Pediatrics 2011;127:511–28. [PubMed]
  7. Reissig CJ, Strain EC, Griffiths RR. Caffeinated energy drinks-a growing problem. Drug Alcohol Depend 2009;99:1–10. [PubMed]
  8. The Daily Mail. Is caffeine in fizzy drinks making teenagers stupid? (25 September 2013). 2013. [Online] (accessed 26 September 2013).
  9. Berger AJ, Alford K. Cardiac arrest in a young man following excess consumption of caffeinated "energy drinks". Med J Aust 2009;190:41–3. [PubMed]
  10. The Age. Caffeine concern over teens and energy drinks (5 September 2013). 2013. [Online] (accessed 23 September).
  11. NSW Poisons Information Centre. 2012 Annual Report. 2012. [Online] (accessed 26 September 2013).
  12. Trapp GS, Allen K, O'Sullivan TA, et al. Energy drink consumption is associated with anxiety in Australian young adult males. Depress Anxiety 2013 Sep 9. doi: 10.1002/da.22175. [Epub ahead of print] [PubMed]
  13. Trapp GS, Allen K, O'Sullivan TA, et al. Energy drink consumption amoung young Australian adults: associations with alcohol and illicit drug use. Drug and Alcohol Dependence In Press. [Fulltext]
  14. Sports drinks and energy drinks for children and adolescents: are they appropriate? Pediatrics 2011;127:1182–9. [PubMed]
  15. Food Standards Australia New Zealand. Standard 2.6.4 Formulated caffeinated beverages. 2013. [Online] (accessed 26 September 2013).