Energy Drinks

    Researchedby:
    Thomas Solomon

    Fact-checked

    by:

    Nick Milazzo, Natalka Roshak
    Last Updated: January 3, 2024

    Energy drinks and shots are beverages that are claimed to increase energy and reduce fatigue. They typically contain caffeine along with a cocktail of other ingredients, including, but not limited to, taurine, glucuronolactone, carnitine, choline, electrolytes, and B vitamins.

    What are energy drinks?

    Energy drinks and energy shots are food supplements that typically contain sugar, artificial sweeteners, and a stimulant like caffeine, taurine, or guarana (which contains caffeine). However, they usually also contain a large array of other substances including glucuronolactone, carnitine, choline, electrolytes (sodium, potassium, magnesium, etc.), and vitamins — vitamin A, vitamin C, vitamin D, and vitamins B3, B6, and B12. Consequently, the composition of different energy drinks and shots is highly variable. For example, the caffeine content of an energy drink can range from 45 to 400 milligrams (174±81 milligrams on average),[5][6] while the sugar content can range from 1 to 63 grams (19.9±18.2 grams on average).[5][6]

    Energy drinks and shots are often known by their brand names — 5-hour Energy, Rockstar Energy, Red Bull, etc. — and are marketed to improve focus, increase energy, and reduce feelings of fatigue. Energy drink consumption is popular worldwide,[7][8][9][10][11] especially in teenagers and young adults,[12][13][14][15] and their market is huge: in 2021, the global market for energy drinks was valued at $86 billion.[16]

    Manufacturers focus their advertisement campaigns at people involved in extreme sports, esports, and people engaged in cognitively demanding work, and use brand ambassadors and sponsored athletes to “influence” engagement.[17] However, in the face of their popularity and claimed effects, several scientists and organizations have raised awareness of the potential adverse health effects of energy drinks and shots, claiming that they’re a public health concern.[18][19][20]

    What are energy drinks’ main benefits?

    Some studies show that energy drinks can reduce feelings of sleepiness and fatigue,[21][22][23] increase feelings of alertness,[24][25] and improve some aspects of cognitive function, including mood,[24] attention,[26][27][24] memory,[28][26][24] and reaction time.[5][29][30][25] Energy drinks have also been shown to reduce ratings of perceived exertion (RPE) during exercise and enhance aerobic and anaerobic exercise performance.[5][31][32][33] However, existing randomized controlled trials examining the effects of energy drinks are few in number, include small numbers of participants, and often lack a control group for each ingredient. Furthermore, existing trials have large variability in the types of participants, testing modalities, and product ingredients. Therefore, further high-quality research is needed to make firm conclusions.

    It is also important to note that caffeine is the primary ingredient — and typically the sole stimulant — added to energy drinks.[5][6] Consequently, it is very likely that caffeine is responsible for the above-described effects of energy drinks because ample evidence shows that all of these effects are also caused by caffeine in isolation.

    What are energy drinks’ main drawbacks?

    Studies examining the effects of energy drinks have highly variable study designs, and long-term randomized controlled trials are lacking.[34] Consequently, further high-quality studies are needed to fully understand the short- and long-term drawbacks of energy drinks and shots. That said, several papers reviewing the evidence from observational studies have highlighted public health concerns about energy drinks, which are due to their numerous side effects and their potential adverse health effects.[18][19][35][20]

    Common side effects of energy drinks include headache, shortness of breath, jitteriness/restlessness, gastrointestinal upset, and sleep problems (e.g., insomnia).[36][37][38][38] Furthermore, observational studies indicate that frequent energy drink consumers are more likely to consume other caffeine-containing beverages,[39] and are also more likely to engage in unhealthy behaviors, such as alcohol, drug use, and smoking, and more likely to make less-healthful dietary choices such as sugar-sweetened beverages and junk foods.[39][40][41][42][43][44]

    Consumption of energy drinks and shots is also associated with increased stress, anxiety, and depression-related symptoms.[45][5][38] However, such health risks are often derived from observational studies involving cross-sectional study designs and correlation analyses, which makes it difficult to be confident about causality. Furthermore, “reverse causation” is also possible — i.e., people with conditions like anxiety or depression might be more likely to consume energy drinks to cope with symptoms. That said, one 2-year observational study found that male participants who went from being a non-energy drink user to an energy drink user had an increase in stress, anxiety, and depression-related symptoms over the course of the study, even after controlling for known confounders.[46] Further studies are needed to make firm conclusions concerning the association between energy drink use and mental health.

    Consuming an energy drink can acutely raise heart rate and blood pressure at rest[47][48][49] and during exercise,[50][47] and delay their recovery following exercise.[50][47] Energy drinks can also disturb electrical activity in the heart: electrocardiogram (ECG) readings show a prolonged QRS complex (the time it takes for heart muscles to contract) and lengthened QTc intervals (the time it takes for heart muscles to relax after they start to contract).[47] The long-term effects of such outcomes are currently unclear, but people with heart conditions should exercise caution when consuming energy drinks and consult their doctor if they are unsure.

    There have been several case reports of adverse cardiovascular events occurring following the consumption of energy drinks and shots.[51][52][53][54][55][56][57] However, these have largely occurred when energy drinks or shots were consumed either in excess or in combination with other substances with potential adverse effects, such as alcohol and drugs.[58] While the population-level incidence of an adverse event is low[59], it’s important to note that, particularly for members of certain groups (children, teenagers, people with underlying heart conditions), dramatically exceeding one's recommended daily caffeine intake limit, whether by energy drinks alone or in combination with other caffeine-containing food and drink, carries risks to one's health.[60][61]

    Do energy drinks cause sleep problems?

    Are energy drinks addictive?

    What are the effects of mixing energy drinks with alcohol?

    How do energy drinks work?

    It is difficult to identify the component of energy drinks responsible for the above-described effects, because most studies do not include the multiple control groups that would be needed to compare the energy drink or shot to each of its listed ingredients. However, caffeine is a likely candidate, because its benefits — improved cognitive function and exercise performance, etc. — and adverse effects — elevated heart rate and blood pressure, sleep disturbance, headaches, etc. — are almost identical to those caused by energy drinks. For more information, please read our article: How does caffeine work?.

    In addition to caffeine, energy drinks also typically contain sugar, which might contribute to the exercise-performance-enhancing effect of energy drinks and shots that has been documented in some studies.[5] However, the sugar content of energy drinks is highly variable (1–63 grams; 19.9±18.2 grams on average),[5][6] and further studies are needed to understand the contribution of energy drinks’ sugar content to the claimed effects.

    Many other ingredients are added to energy drinks and shots: taurine, glucuronolactone, carnitine, choline, electrolytes, vitamin A, vitamin C, vitamin D, and vitamins B3 (niacin), B6, and B12. The known effects of these ingredients do not align with the claimed benefits of energy drinks and shots. That said, some studies have found greater disturbances in blood pressure and in the heart’s electrical activity after consumption of an energy drink than after a drink containing identical amounts of caffeine, but lacking the energy drink’s other ingredients.[62][63] This suggests that some energy drink ingredients besides caffeine may also have detrimental effects. However, the problem is that most studies simply compare an energy drink to water, rather than having a control group for each ingredient (e.g., energy drink vs. water, vs. water+caffeine, vs. water+taurine, vs. water+sugar, etc.). Therefore, the additional ingredients in energy drinks have not been studied in adequate detail to fully understand their benefits or risks, or the lack thereof.[18] Consequently, further high-quality research is necessary to fully understand how energy drinks cause their benefits and drawbacks.

    What are other names for Energy Drinks

    Note that Energy Drinks is also known as:
    • Redbull Energy Drink
    • Monster Energy Drink
    • Full Throttle Energy Drink
    • NOS Energy Drink
    Energy Drinks should not be confused with:
    • Caffeine (often a main ingredient but not the sole ingredient)

    Dosage information

    There are no specific dosing suggestions for energy drinks or energy shots, but there are upper limits of suggested daily intake for some of the substances found in them.

    For example, according to the US Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA), caffeine is unlikely to cause detrimental health effects if daily intake is below 400 mg/day in non-pregnant adults or below 200 mg/day in pregnant/lactating women, and if a single dose is less than 200 mg.[1][2] While more research is needed to clarify the safety and upper limits of intake for children and adolescents,[1] one systematic review suggests that this age group should consume no more than 2.5 mg of caffeine per kilogram of bodyweight per day (equivalent to 100 mg for a 40 kg person),[3] and some organizations discourage children and adolescents from consuming caffeine and other stimulants at all.[2]

    Because some energy drinks and shots contain very high amounts of caffeine, and because high caffeine intake can cause serious adverse effects, the FDA recommends avoiding dietary supplements that contain highly concentrated caffeine since they can far exceed the upper recommended limit of daily intake.[4] For a detailed overview of caffeine dosing, read our article “How Much Caffeine Is Too Much?”.

    To learn more about the specific ingredients in energy drinks and shots, visit our pages on sugar, artificial sweeteners, caffeine, taurine, guarana, glucuronolactone, carnitine, choline, electrolytes, vitamin A, vitamin C, vitamin D, and the B vitamins, including B3 (niacin), B6, and B12.

    Frequently asked questions

    What are energy drinks?

    Energy drinks and energy shots are food supplements that typically contain sugar, artificial sweeteners, and a stimulant like caffeine, taurine, or guarana (which contains caffeine). However, they usually also contain a large array of other substances including glucuronolactone, carnitine, choline, electrolytes (sodium, potassium, magnesium, etc.), and vitamins — vitamin A, vitamin C, vitamin D, and vitamins B3, B6, and B12. Consequently, the composition of different energy drinks and shots is highly variable. For example, the caffeine content of an energy drink can range from 45 to 400 milligrams (174±81 milligrams on average),[5][6] while the sugar content can range from 1 to 63 grams (19.9±18.2 grams on average).[5][6]

    Energy drinks and shots are often known by their brand names — 5-hour Energy, Rockstar Energy, Red Bull, etc. — and are marketed to improve focus, increase energy, and reduce feelings of fatigue. Energy drink consumption is popular worldwide,[7][8][9][10][11] especially in teenagers and young adults,[12][13][14][15] and their market is huge: in 2021, the global market for energy drinks was valued at $86 billion.[16]

    Manufacturers focus their advertisement campaigns at people involved in extreme sports, esports, and people engaged in cognitively demanding work, and use brand ambassadors and sponsored athletes to “influence” engagement.[17] However, in the face of their popularity and claimed effects, several scientists and organizations have raised awareness of the potential adverse health effects of energy drinks and shots, claiming that they’re a public health concern.[18][19][20]

    What are energy drinks’ main benefits?

    Some studies show that energy drinks can reduce feelings of sleepiness and fatigue,[21][22][23] increase feelings of alertness,[24][25] and improve some aspects of cognitive function, including mood,[24] attention,[26][27][24] memory,[28][26][24] and reaction time.[5][29][30][25] Energy drinks have also been shown to reduce ratings of perceived exertion (RPE) during exercise and enhance aerobic and anaerobic exercise performance.[5][31][32][33] However, existing randomized controlled trials examining the effects of energy drinks are few in number, include small numbers of participants, and often lack a control group for each ingredient. Furthermore, existing trials have large variability in the types of participants, testing modalities, and product ingredients. Therefore, further high-quality research is needed to make firm conclusions.

    It is also important to note that caffeine is the primary ingredient — and typically the sole stimulant — added to energy drinks.[5][6] Consequently, it is very likely that caffeine is responsible for the above-described effects of energy drinks because ample evidence shows that all of these effects are also caused by caffeine in isolation.

    What are energy drinks’ main drawbacks?

    Studies examining the effects of energy drinks have highly variable study designs, and long-term randomized controlled trials are lacking.[34] Consequently, further high-quality studies are needed to fully understand the short- and long-term drawbacks of energy drinks and shots. That said, several papers reviewing the evidence from observational studies have highlighted public health concerns about energy drinks, which are due to their numerous side effects and their potential adverse health effects.[18][19][35][20]

    Common side effects of energy drinks include headache, shortness of breath, jitteriness/restlessness, gastrointestinal upset, and sleep problems (e.g., insomnia).[36][37][38][38] Furthermore, observational studies indicate that frequent energy drink consumers are more likely to consume other caffeine-containing beverages,[39] and are also more likely to engage in unhealthy behaviors, such as alcohol, drug use, and smoking, and more likely to make less-healthful dietary choices such as sugar-sweetened beverages and junk foods.[39][40][41][42][43][44]

    Consumption of energy drinks and shots is also associated with increased stress, anxiety, and depression-related symptoms.[45][5][38] However, such health risks are often derived from observational studies involving cross-sectional study designs and correlation analyses, which makes it difficult to be confident about causality. Furthermore, “reverse causation” is also possible — i.e., people with conditions like anxiety or depression might be more likely to consume energy drinks to cope with symptoms. That said, one 2-year observational study found that male participants who went from being a non-energy drink user to an energy drink user had an increase in stress, anxiety, and depression-related symptoms over the course of the study, even after controlling for known confounders.[46] Further studies are needed to make firm conclusions concerning the association between energy drink use and mental health.

    Consuming an energy drink can acutely raise heart rate and blood pressure at rest[47][48][49] and during exercise,[50][47] and delay their recovery following exercise.[50][47] Energy drinks can also disturb electrical activity in the heart: electrocardiogram (ECG) readings show a prolonged QRS complex (the time it takes for heart muscles to contract) and lengthened QTc intervals (the time it takes for heart muscles to relax after they start to contract).[47] The long-term effects of such outcomes are currently unclear, but people with heart conditions should exercise caution when consuming energy drinks and consult their doctor if they are unsure.

    There have been several case reports of adverse cardiovascular events occurring following the consumption of energy drinks and shots.[51][52][53][54][55][56][57] However, these have largely occurred when energy drinks or shots were consumed either in excess or in combination with other substances with potential adverse effects, such as alcohol and drugs.[58] While the population-level incidence of an adverse event is low[59], it’s important to note that, particularly for members of certain groups (children, teenagers, people with underlying heart conditions), dramatically exceeding one's recommended daily caffeine intake limit, whether by energy drinks alone or in combination with other caffeine-containing food and drink, carries risks to one's health.[60][61]

    Do energy drinks cause sleep problems?

    Energy drink use is associated with sleep disturbance.[36][38] This is likely due to caffeine, which is well known to reduce sleep duration and impair sleep quality.[64][65] A recent meta-analysis found that to prevent deleterious effects on subsequent sleep, caffeine-containing supplements should be consumed at least 13 hours before bedtime.[64]

    Are energy drinks addictive?

    Currently, no direct evidence indicates that energy drinks and shots are addictive. However, caffeine, which is found in such products, can cause mild drug dependence and withdrawal symptoms (headache, drowsiness, and irritability) in some people.[66]

    What are the effects of mixing energy drinks with alcohol?

    Energy drink use is associated with other unhealthy dietary habits, including alcohol consumption.[41][42][44] This is concerning because the current evidence shows that adults and adolescents who consume energy drinks with alcohol report more hazardous alcohol consumption patterns and more frequent risk-taking behavior (speeding, fighting, unprotected sex, etc) than people who consume alcohol alone.[67][68][69] Combined energy drink and alcohol consumption is also associated with increased prevalence of other unhealthy behaviors, including daily smoking, binge drinking, use of psychotropic drugs.[69] However, these lines of evidence are derived from observational studies with cross-sectional study designs, and further high-quality research (randomized controlled trials and cohort studies) is required to understand the direct effects of energy drinks plus alcohol on health outcomes.

    How do energy drinks work?

    It is difficult to identify the component of energy drinks responsible for the above-described effects, because most studies do not include the multiple control groups that would be needed to compare the energy drink or shot to each of its listed ingredients. However, caffeine is a likely candidate, because its benefits — improved cognitive function and exercise performance, etc. — and adverse effects — elevated heart rate and blood pressure, sleep disturbance, headaches, etc. — are almost identical to those caused by energy drinks. For more information, please read our article: How does caffeine work?.

    In addition to caffeine, energy drinks also typically contain sugar, which might contribute to the exercise-performance-enhancing effect of energy drinks and shots that has been documented in some studies.[5] However, the sugar content of energy drinks is highly variable (1–63 grams; 19.9±18.2 grams on average),[5][6] and further studies are needed to understand the contribution of energy drinks’ sugar content to the claimed effects.

    Many other ingredients are added to energy drinks and shots: taurine, glucuronolactone, carnitine, choline, electrolytes, vitamin A, vitamin C, vitamin D, and vitamins B3 (niacin), B6, and B12. The known effects of these ingredients do not align with the claimed benefits of energy drinks and shots. That said, some studies have found greater disturbances in blood pressure and in the heart’s electrical activity after consumption of an energy drink than after a drink containing identical amounts of caffeine, but lacking the energy drink’s other ingredients.[62][63] This suggests that some energy drink ingredients besides caffeine may also have detrimental effects. However, the problem is that most studies simply compare an energy drink to water, rather than having a control group for each ingredient (e.g., energy drink vs. water, vs. water+caffeine, vs. water+taurine, vs. water+sugar, etc.). Therefore, the additional ingredients in energy drinks have not been studied in adequate detail to fully understand their benefits or risks, or the lack thereof.[18] Consequently, further high-quality research is necessary to fully understand how energy drinks cause their benefits and drawbacks.

    Other FAQs
    Do I need to cycle caffeine?
    Quick answer:

    There are benefits associated with chronic caffeine consumption, and there are benefits associated with acute caffeine consumption that fade with tolerance; if you like the latter, cycling is mandatory. If you like the former, cycling is not needed.

    Chronic non-cycled caffeine consumption (in the form of coffee and tea, both of which contain many bioactive components in addition to caffeine) is associated with a reduced risk of several diseases, including Parkinson’s disease, type 2 diabetes, and chronic liver disease.[61] Caffeine consumption has also been shown to enhance performance on attention tasks, regardless of the participants’ caffeine consumption habits.[70] Clearly, cycling isn’t needed to obtain these benefits. So why cycle? The question usually comes up in the context of exercise performance enhancement.

    Supplementation with 3–6 mg of caffeine per kg of body weight before exercise has been consistently shown to enhance performance over a wide range of exercise intensities and durations, with beneficial effects on aerobic exercise performance, muscular endurance and strength, sprinting, jumping, and throwing performance.[71]

    Caffeine elicits an ergogenic effect (i.e., enhances exercise performance) primarily by affecting the central nervous system. Caffeine blocks adenosine receptors in the brain, resulting in increased release of neurotransmitters such as dopamine and norepinephrine, and thus increased alertness and focus. It can also reduce pain and perceived exertion during exercise.

    It seems to many habitual caffeine users that habitual use reduces, or even eliminates, the ergogenic effect of acute caffeine ingestion. The rationale is that habitual caffeine use increases the number of adenosine receptors in the brain, and as such, reduces the adenosine-blocking effect of caffeine. This has been shown in rodents,[72][73] but has yet to be studied in humans. Evidence from human studies does suggest that habitual caffeine use can blunt some aspects of the physiological response to caffeine, such as an increase in plasma epinephrine levels.[74][75]

    In further support of the idea that athletes should cycle caffeine in order to maximize its ergogenic effect, some studies indicate that when individuals with low habitual caffeine intake (< 75 mg/day) consume 3 mg of caffeine per kg of body weight daily for 20–28 days, the ergogenic effect of caffeine is reduced.[76][77]

    However, in a 2022 meta-analysis of 59 studies that investigated the effect of acute supplementation with caffeine on exercise performance in habitual caffeine consumers, it was found that acute supplementation with caffeine improved performance during endurance, power, and strength exercises.[78] Moreover, the performance-enhancing effects of an acute dose of caffeine were independent of whether or not that dose was greater or smaller than participants' habitual consumption, as well as being independent of sex or training status.

    The results of this meta-analysis indicate that caffeine does not lose its ergogenicity with chronic use; that is, even with daily caffeine consumption, ingesting some caffeine about an hour before exercise will still have a positive impact on performance in people who benefit from caffeine (which is not everyone). But is it possible that skipping a cup of coffee today will enhance the effects of a cup of coffee on exercise performance tomorrow? Probably not.

    Two separate studies reported that abstaining from caffeine for four days prior to an exercise test did not enhance the effect of acute supplementation with caffeine,[79][80] and shorter withdrawal periods (24–48 hours) don’t appear to be useful either.[78] Therefore, the available evidence does not support the common practice of utilizing a caffeine withdrawal period before an important training session or competition to maximize caffeine’s ergogenic effect. In fact, doing so may even be detrimental, as a four-day withdrawal period was found to result in a number of side effects, including headaches, fatigue, impaired focus, and a lack of motivation.

    It remains to be determined whether a longer withdrawal period can boost caffeine’s ergogenic effect, but considering the fact that acute supplementation with caffeine enhances exercise performance in habitual users, and abstaining from caffeine tends to result in unfavorable symptoms, the juice is unlikely to be worth the squeeze if the purpose of a caffeine withdrawal period is solely to maximize caffeine’s ergogenic effect on a specific day.

    Update History

    References

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