Side Effects of Energy Drinks: Their Ingredients and Concerns

Side Effects of Energy Drinks: Their Ingredients and Concerns

by Sanjay B

The side effects of energy drinks have been extensively studied. The apparent increase in energy comes from caffeine and sugar and not added natural ingredients as often claimed. The combination of energy drinks and alcohol is potentially lethal.

The side effects of energy drinks on body are not widely appreciated, even though they are extremely popular. They are claimed to boost energy, and while much of this ‘energy’ comes from the sugar and caffeine content of such drinks, those that market them claim this comes largely from the other ingredients. Among these are B vitamins, amino acids and herbal stimulants.

The dangers of energy drinks do not lie so much in these ingredients, but in their caffeine content and also in the common practice of mixing them alcohol. Red Bull and alcohol is a very popular drink, the alcohol normally coming in the form of vodka or white rum. The dangers of these mixtures will be discussed in detail later. For now, let’s look at caffeine and ask why the manufacturers play down the caffeine content of their energy drinks and focus on the other added ingredients.

Herbal Ingredients in Energy Drinks

Manufactures claim that the natural herbal ingredients of their drinks offer you increase energy and alertness.  Among these herbal ingredients are acai, milk thistle, ginkgo biloba and ginseng. These are generally present is small amounts and should generally do no harm – nor will they do much good for your energy in the concentrations present.

Guarana is also present. This is a South American bean and contains 2-3 times the amount of caffeine as coffee beans. It also contains theobromine and theophylline, similar to caffeine and which are also found in chocolate.  They, like caffeine, are heart stimulants. Some people find the caffeine found in guarana to be more of a stimulant than that from coffee, though others report the opposite.

Other Ingredients of Energy Drinks

Such drinks also contain substances such as inositol, a safe substance generated by your own metabolism and which supports the nervous system. Taurine is an amino acid that helps calm the brain, and perhaps enables you handle better the excitable state that caffeine can promote. Other amino acids are often present in small quantities and also the B vitamins previously mentioned.

Ginseng helps increase energy levels and relieves stress.  It also stimulates the pituitary and hypothalamic glands. Gingko Biloba helps improve circulation to the extremities and improve memory. They can also contain other amino acids and artificial sweeteners, the latter of which present their own health problems in addition to the caffeine content and sugar discussed below.

Caffeine in Energy Drinks

This is all very interesting – but largely irrelevant, because in spite of what the manufacturers will tell you, the energy stimulation effects of energy drinks come from their sugar and caffeine content. There is little scientific evidence to indicate that the other ingredients offer much energy, or any other benefits, from the small quantities that are present. Acai, for example, does no more than offer a slight color and some of the others are present is such low quantities that they seem present only to impress.

The majority of energy drinks contain from 70mg to 200mg caffeine. A can of coke contains 34mg, instant coffee up to 80mg and filtered drip coffee up to 150mg, the latter two per 8 ounce cup. Caffeine is a stimulant that raises the heart rate and blood pressure, and also stimulates the central nervous system.

Reported Side Effects

Although excessive consumption of caffeine can initially give rise to a feeling of euphoria, the side effects of energy drinks can include anxiety, agitation and insomnia [1]. Caffeine withdrawal can affect athletic performance and mood [2].  However, energy drinks can also temporarily improve alertness and athletic performance.

Although studies have indicated that taking one average can or bottle of energy drink each day will not result in excessive caffeine intake, two or more such drinks could, with specific side effects when taken in conjunction with antidepressants [3]. Another problem is that such drinks contain few electrolytes, leading to an increase likelihood of burn-out after high-energy activity. Not only that, but the body tends to dilute sugar present in high concentrations  such as are found in many energy drinks, and caffeine  promotes this, a possible consequence being dehydration. Even just 1% dehydration will reduce performance by 10% [4].

Among the reported side effects of energy drinks reported in the USA are nausea an irregular heartbeat, and visits to emergency rooms have also been reported, while the burn-out after the energy high can result in seizures.

Caffeine and Alcohol: A Lethal Combination

There are few doubts that most of the dangers of energy drinks lie in their caffeine content, yet it is not mandatory in the USA for such drinks to be labeled with their caffeine content. Unlike cola drinks, the caffeine content of energy drinks is not FDA regulated. An even greater risk is involved when energy drinks such as red Bull are taken with alcohol. This is a popular combination, yet the risk is high and potentially lethal.

The combination of a stimulant and a depressant can provide an unawareness of one’s level of intoxication, and such people have been estimated to be four times more liable to drink and drive or to take other risks while intoxicated. Other risks lie in the artificial sweeteners present, such as aspartame and sucralose that can be included even when sugar is present.

The bottom line is that energy drinks and energy ‘shots’ carry a great risk to those taking them to excess, and particularly when taken with alcohol and medications such as Ritalin. The side effects of energy drinks include elevated heart rate, increased blood pressure, dehydration, energy spikes and crashes, seizures and weight gain.

This is not opinion, but is supported by studies that have been extensively reported in scientific literature.


1.  Alford, C; Cox, H; Wescott, R (2001). “The effects of red bull energy drink on human performance and mood“. Amino Acids 21 (2): 139–50

2.  Yeomans, MR; Ripley, T; Davies, LH; Rusted, JM; Rogers, PJ (2002). “Effects of caffeine on performance and mood depend on the level of caffeine abstinence“. Psychopharmacology 164 (3): 241–9.

3.  Winston, AP et al. (2005). Neuropsychiatric effects of caffeine. Advances in Psychiatric Treatment 11 (6): 432.

4.  pp12-13.

Other Reading:

Howard, MA; Marczinski, CA (2010). “Acute effects of a glucose energy drink on behavioral control“. Experimental and Clinical Psychopharmacology 18 (6): 553–61.

Heckman, Melanie. “Caffeine (1, 3, 7-trimethylxanthine) in Foods: A Comprehensive Review on Consumption, Functionality, Safety, and Regulatory Matters.”. Journal of Food and Science. Retrieved 14 November 2011.

Iyadurai, S; Chung, S (2007). “New-onset seizures in adults: Possible association with consumption of popular energy drinks“. Epilepsy & Behavior 10 (3): 504.

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