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The Energy Drink

By Scott Gavura, BScPhm, MBA, RPh for Science-Based Medicine

My stimulant of choice is coffee. I started drinking it in first-year university, and never looked back. A tiny four-cup coffee maker became my reliable companion right through graduate school.

But since I stopped needing to drink a pot at a time, an entirely new category of products has appeared — the energy drink. Targeting students, athletes, and others seeking a mental or physical boost, energy drinks are now an enormous industry: From the first U.S. product sale in 1997, the market size was $4.8 billion by 2008, and continues to grow. (1)

My precious coffee effectively has a single therapeutic ingredient, caffeine. Its pharmacology is well documented, and the physiologic effects are understood. The safety data isn’t too shabby either: it’s probably not harmful and possibly is even beneficial. (I’m talking about oral consumption — no coffee enemas. Please.) In comparison, energy drinks are a bewildering category of products with an array of ingredients including caffeine, amino acids, vitamins, and other “natural” substances and assorted “nutraceuticals,” usually in a sugar-laden vehicle (though sugar-free versions exist). Given many products contain chemicals with pharmacologic effects, understanding the risks, signs of adverse events, and potential implications on drug therapy, are important.

So are energy drinks just candied caffeine delivery systems? Or are these syrupy supplements skirting drug regulations?

The Message

The ads are seductive. Who doesn’t want more energy? Who doesn’t want their mind and body “vitalized?” And don’t we have time-starved lifestyles? Initially envisioned for athletes, energy drinks are now marketed mainly towards teens and young adults, where uptake has been dramatic. Cross-promotion with extreme sporting events, and creating names like “Full Throttle,” “Rockstar,” and even  “Cocaine” burnish the “extreme” image. The market is now segmented further with products targeted at women, vegetarians, diabetics, celiacs, and more. However you identify yourself, there’s probably an energy drink developed with you in mind.

The Ingredients

Evaluating claims of efficacy and safety are complicated by the multiple formulations and versions of the products. Most energy drinks contain these ingredients:

Ginseng is often claimed to have remarkable properties, from preventing colds to acting as an immune “booster”, but there’s actually little evidence to suggest it has any of these effects. Studies looking specifically at performance effects have not been impressive. (2) Furthermore, the doses that have been studied significantly exceed the amounts that are found in energy drinks. At low doses ginseng seems safe, but there’s not a lot of long-term data to reassure us. (3)

Taurine is an amino acid that is is plentiful in our diets, and can also be endogenously manufactured. It’s involved in an array of physiologic functions. What’s not clear is if exogenous taurine supplements have any meaningful effect on subjective or objectively measures of “energy” or performance. There are limited data evaluating taurine in combination with caffeine, but high quality evidence is lacking. Taurine does seem to be reasonably well tolerated, however, with few adverse events reported or expected. (3)

Glucuronolactone is another natural ingredient of food for which there’s no evidence of deficiency, nor any evidence that supplementation improves energy level. Consumption at the levels present in energy drinks is considered safe.

Bitter Orange is the peel or oil from Seville oranges. It became a popular ingredient in supplements after ephedra was pulled from the U.S. market. A natural source of epinephrine-like compounds, it shares the same adverse effect profile, with links to serious events such as syncope, heart attacks, colitis, and stroke. There’s no persuasive evidence demonstrating bitter orange provides any energy boost, particularly at the low levels present in energy drinks. However, given bitter orange is usually combined with other stimulants, the true pharmacologic profile, and consequent adverse effects, may not be clear. (3)

Caffeine and guarana (a natural source of caffeine) are the most relevant ingredients in energy drinks. Caffeine has a variety of physiologic effects, and while it appears to have value improving endurance and reducing fatigue during sustained physical exercise, its role as a cognition booster seems much more tenuous. It also seems to improve the effectiveness of analgesics, and may possibly have its own analgesic properties. In general caffeine has a reasonable safety profile at moderate doses. (3)

While total amount of caffeine in an energy drink may not be listed, as natural sources may not be included in the nutritional information, coffee has more caffeine than many energy drinks. A 16 oz “grande” coffee at Starbucks has 320mg of caffeine; the 20oz “venti” has 400mg. (For Tim Hortons lovers, there’s about half that much caffeine in your double-double). In comparison, a Red Bull has 151mg/16 oz, Monster Khaos has 150mg/16oz, and Rockstar Punched has 160mg/16oz. And a 573mL can of Coca Cola (19oz) has a piddly 62mg. If you accept that caffeine is worth consuming, then energy drinks are clearly not the best source. Even factoring in the caffeine from guarana, coffees still appears to be the caffeine king. (CSPI has a nice compilation of the caffeine content of different beverages.)Besides, there’s always Nodoz.

Vitamins are in many of the energy drinks: especially combinations of the B vitamins, like cyanocobalamin (B12), niacinamide (B3), pantothenic acid (B5) and pyridoxine (B6). Vitamin C is also common. In the absence of a deficiency, there isn’t any persuasive evidence to suggest that supplementation has meaningful effects on “energy,” however defined. (3) Even long term use of the B vitamins doesn’t look promising for cognition.

Sugar is the major sweetener in energy drinks, though sugar-free versions exist. Speaking strictly in terms of chemistry, as a carbohydrate, sugar is the only actual energy in an energy drink. (The “calorie free energy drink” ads make me laugh out loud.) The sugar content of most products seems largely similar to colas and other soft drinks. So if you want to carb-load, there’s no particular advantage to the energy drinks — sugar is sugar, and calories are calories.


Side effects related to energy drinks appear to be largely due to the caffeine content. Thresholds are difficult to predict, given that tolerances to caffeine can vary. In general, the amounts of taurine, guarana, and other components are felt to be below the level necessary to cause noticeable adverse effects.(2) While there have been serious adverse events reported with energy drinks including seizures and sudden death, clear causation has not been established.

Probably the biggest concern related to energy drinks is their consumptions by youths and adolescents, where caffeine’s effects are less well understood. Sugar and caffeine consumption are probably best minimized in this population, yet it’s clear that this is the target consumer.

The combination of energy drinks with alcohol — they are popular mixers — has been linked to a suppression of the traditional intoxication effects.There’s controversy over the sale of the deliberate combinations of the two ingredients, and some regulators have taken action to stop the sales of some products.


Regulation of energy drinks varies by country. From an international perspective, the United States has one of the least regulated marketplaces. (1) Caffeine limits that apply to cola drinks do not apply to energy drinks. In Canada, some energy drinks are federally approved as natural health products. For example,  the authorized recommended use for Red Bull is:

Developed for periods of increased mental and physical exertion, helps temporarily restore mental alertness or wakefulness when experiencing fatigue or drowsiness.

The product has a specific caution not to consume more than 500mL (2 cans) per day, and that it is not recommended for children, pregnant, or breastfeeding women.

Given their noveltly in the market, and their growing popularity, expect regulatory approaches to vary around the world. Products like Red Bull have been subject to regulatory restrictions and even bans in some European countries.


Neither innocuous nor toxic, energy drinks seem safe for adults when consumed in moderation. There’s no convincing evidence to back up the cognitive or athletic performance enhancement claims attached to the category, or to specific products. Despite the impressive lists of ingredients and slick marketing, these products are essentially caffeine delivery vehicles, most of which come loaded with sugar. The incremental risk from the other ingredients isn’t well understood, but is probably small when consumed occasionally.

So go ahead and enjoy your Red Bull. But when that liquid candy stops appealing to you, I’ve got some shade-grown, bird-friendly, passive-organic, fair-trade, home-roasted coffee for you to try.


1. Heckman, M., Sherry, K., & De Mejia, E. (2010). Energy Drinks: An Assessment of Their Market Size, Consumer Demographics, Ingredient Profile, Functionality, and Regulations in the United States Comprehensive Reviews in Food Science and Food Safety, 9 (3), 303-317 DOI: 10.1111/j.1541-4337.2010.00111.x

2. Clauson, K., Shields, K., McQueen, C., & Persad, N. (2008). Safety issues associated with commercially available energy drinks Journal of the American Pharmacists Association, 48 (3) DOI: 10.1331/JAPhA.2008.07055

3. Natural Medicines Comprehensive Database. Subscription required to view.

*This blog post was originally published at Science-Based Medicine*

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