Energy drinks are intended to boost your energy, alertness and concentration.
People of all ages consume them and they continue to grow in popularity.
But some health professionals have warned that energy drinks may have harmful consequences, which has led many people to question their safety.
This article weighs the good and the bad of energy drinks, providing an extensive review of their health effects.
Energy drinks are beverages that contain ingredients marketed to increase energy and mental performance.
Red Bull, 5-Hour Energy, Monster, AMP, Rockstar, NOS and Full Throttle are examples of popular energy drink products.
Nearly all energy drinks contain the ingredient caffeine to stimulate brain function and increase alertness and concentration.
However, the amount of caffeine differs from product to product. This table shows the caffeine content of some popular energy drinks:
|Product Size||Caffeine Content|
|Red Bull||8.4 oz (250 ml)||80 mg|
|AMP||16 oz (473 ml)||142 mg|
|Monster||16 oz (473 ml)||160 mg|
|Rockstar||16 oz (473 ml)||160 mg|
|NOS||16 oz (473 ml)||160 mg|
|Full Throttle||16 oz (473 ml)||160 mg|
|5-Hour Energy||1.93 oz (57 ml)||200 mg|
All caffeine information in this table was obtained from the manufacturer's website or from Caffeine Informer, if the manufacturer did not list caffeine content.
Energy drinks also typically contain several other ingredients. A few of the most common ingredients other than caffeine are listed below:
- Sugar: Usually the main source of calories in energy drinks, although some do not contain sugar and are low-carb friendly.
- B vitamins: Play an important role in converting the food you eat into energy your body can use.
- Amino acid derivatives: Examples are taurine and L-carnitine. Both are naturally produced by the body and have roles in several biological processes.
- Herbal extracts: Guarana is likely included to add more caffeine, while ginseng may have positive effects on brain function (1).
Summary: Energy drinks are designed to increase energy and mental performance. They contain a combination of caffeine, sugar, vitamins, amino acid derivatives and herbal extracts.
People consume energy drinks for a variety of reasons.
One of the most popular is to increase mental alertness by improving brain function.
But does research really show energy drinks can provide this benefit? Multiple studies confirm that energy drinks can indeed improve measures of brain function like memory, concentration and reaction time, while also reducing mental fatigue (, , ).
In fact, one study, in particular, showed that drinking just one 8.4-ounce (500-ml) can of Red Bull increased both concentration and memory by about 24% ().
Many researchers believe this increase in brain function can solely be attributed to caffeine, while others have speculated that the combination of caffeine and sugar in energy drinks is necessary to see the most benefit ().
Summary: Multiple studies have shown energy drinks can reduce mental fatigue and improve measures of brain function, such as memory, concentration and reaction time.
Another reason people consume energy drinks is to help them function when they're sleep-deprived or tired.
Drivers on long, late-night road trips often reach for energy drinks to help them stay alert while they're behind the wheel.
Multiple studies using driving simulations have concluded that energy drinks can increase driving quality and reduce sleepiness, even in drivers who are sleep-deprived (, ).
Similarly, many night-shift workers use energy drinks to help them fulfill job requirements during hours when most people are sound asleep.
Although energy drinks may also help these workers stay alert and awake, at least one study has suggested that energy drink use could negatively affect sleep quality following their shift ().
Summary: Energy drinks can help people function while they're tired, but people may observe decreases in sleep quality following energy drink use.
Research indicates that energy drinks can improve brain function and help you stay alert when you're tired.
However, there are also concerns that energy drinks may contribute to heart problems.
One review showed that energy drink use has been implicated in several cases of heart problems, which required emergency room visits ().
Additionally, over 20,000 trips to the emergency department are associated with energy drink use every year in the US alone ().
Furthermore, multiple studies in humans have also shown that consuming energy drinks may increase blood pressure and heart rate and decrease important markers of blood vessel function, which could be bad for heart health (, ).
Most experts believe that heart problems associated with energy drink use occur as a result of excessive caffeine intake.
This seems reasonable, since many of the people who suffered serious heart problems after drinking energy drinks were consuming more than three energy drinks at a time or also mixing them with alcohol.
Although you may need to be cautious about using energy drinks if you have a history of heart disease, consuming them occasionally and in reasonable amounts is unlikely to cause heart problems in healthy adults with no history of heart disease.
Summary: Several people have developed heart problems after consuming energy drinks, possibly due to drinking too much caffeine or mixing energy drinks with alcohol.
Most energy drinks contain a sizable amount of sugar.
For example, one 8.4-ounce (250-ml) can of Red Bull contains 27 grams (about 7 teaspoons) of sugar, while a 16-ounce (473-ml) can of Monster contains about 54 grams (about 14 teaspoons) of sugar.
Consuming this much sugar will cause anyone's blood sugar to spike, but if you have difficulty controlling your blood sugar or have diabetes, you should be particularly cautious with energy drinks.
Consuming beverages sweetened with sugar, like most energy drinks, leads to blood sugar elevations that can be bad for health, especially if you have diabetes.
These blood sugar elevations have been associated with increased levels of oxidative stress and inflammation, which have been implicated in the development of nearly every chronic disease (, , ).
But even people without diabetes may need to be concerned about the sugar in energy drinks. One study reported that drinking one or two sugar-sweetened beverages daily was correlated with a 26% higher risk of type 2 diabetes ().
Luckily, many energy drink manufacturers are now making products that are either lower in sugar or have eliminated it altogether. These versions are more suitable for people with diabetes or those trying to follow a low-carb diet.
Summary: People with diabetes should opt for low- or no-sugar versions of energy drinks to avoid harmful elevations in blood sugar.
Mixing energy drinks with alcohol is incredibly popular among young adults and college students.
However, this presents a major public health concern.
The stimulating effects of caffeine in energy drinks can override the depressive effects of alcohol. This can leave you feeling less intoxicated while still experiencing alcohol-related impairments (, ).
This combination can be very troubling. People who ingest energy drinks with alcohol tend to report heavier alcohol consumption. They're also more likely to drink and drive, and suffer from alcohol-related injuries (, , ).
Furthermore, one study of 403 young Australian adults showed that people were nearly six times more likely to experience heart palpitations when they drank energy drinks mixed with alcohol compared to when they drank alcohol alone ().
Pre-mixed alcoholic energy drinks rose in popularity in the mid-2000s, but in 2010 the US Food and Drug Administration (FDA) forced companies to remove stimulants from alcoholic beverages following reports of medical problems and deaths.
Still, many individuals and bars continue to mix energy drinks and alcohol on their own. For the above reasons, it is not recommended to consume energy drinks mixed with alcohol.
Summary: Energy drinks mixed with alcohol can leave you feeling less intoxicated while still experiencing alcohol-related impairments. Consuming energy drinks with alcohol is not recommended.
An estimated 31% of children aged 12–17 regularly consume energy drinks.
However, according to recommendations published by the American Academy of Pediatrics in 2011, energy drinks should not be consumed by children or teenagers ().
Their reasoning is that the caffeine found in energy drinks places children and teenagers at risk of becoming dependent or addicted to the substance, and may also have negative effects on the developing heart and brain ().
Experts also set caffeine limits for these ages, recommending that teenagers consume no more than 100 mg of caffeine daily and children consume less than 1.14 mg of caffeine per pound (2.5 mg/kg) of their own body weight per day ().
This is equivalent to about 85 mg of caffeine for a 75-pound (34-kg) child 12 years of age or younger.
Depending on an energy drink's brand and container size, it would not be difficult to exceed these caffeine recommendations with just one can.
Summary: Because of the potential negative effects of caffeine in this population, leading health care organizations discourage the use of energy drinks in children and teenagers.
Most of the health concerns involving energy drinks center on their caffeine content.
Importantly, it is generally recommended that adults consume no more than 400 mg of caffeine per day.
Energy drinks typically only contain around 80 mg of caffeine per 8 ounces (237 ml), which is pretty close to an average cup of coffee.
The problem is that many energy drinks are sold in containers larger than 8 ounces (237 ml). Additionally, some contain more caffeine, especially "energy shots" like 5-Hour Energy, which has 200 mg of caffeine in only 1.93 ounces (57 ml).
On top of that, several energy drinks also contain herbal extracts like guarana, a natural source of caffeine that contains around 40 mg of caffeine per gram (24).
Energy drink manufacturers are not required to include this in the caffeine content listed on the product label, which means the total caffeine content of many beverages can be drastically underestimated.
Depending on the type and size of the energy drink you consume, it is not hard to exceed the recommended amount of caffeine if you consume multiple energy drinks in one day.
Although occasionally drinking one energy drink is unlikely to cause any harm, it is probably wise to avoid consuming energy drinks as a part of your daily routine.
If you decide to consume energy drinks, limit them to no more than 16 ounces (473 ml) of a standard energy drink per day and try to limit all other caffeinated beverages to avoid excessive intake of caffeine.
Pregnant and nursing women, children and teenagers should avoid energy drinks altogether.
Summary: Occasionally drinking one energy drink is unlikely to cause problems. To reduce potential harm, limit your consumption to 16 ounces (473 ml) daily and avoid all other caffeinated beverages.
Energy drinks can deliver on some of their promised benefits by increasing brain function and helping you function when you're tired or sleep-deprived.
However, there are a number of health concerns with energy drinks, particularly related to excessive caffeine intake, sugar content and mixing them with alcohol.
If you choose to drink energy drinks, limit your intake to 16 ounces (473 ml) per day and stay away from "energy shots." Additionally, try to reduce your intake of other caffeinated beverages to avoid the harmful effects of too much caffeine.
Some people, including pregnant and nursing women, children and teenagers, should avoid energy drinks altogether.