7 side effects of energy drinks

A man and a woman drinking energy drinks

Key takeaways:

  • Energy drinks are beverages known for their caffeine content. While some of them are touted for boosting energy and increasing alertness, evidence has shown that they can cause some side effects.
  • Some possible side effects of energy drinks include caffeine addiction, weight gain, and increased anxiety.
  • When it comes to beverages, particularly caffeinated ones, the key is moderation. Some of them contain unhealthy ingredients, such that one consumed especially excessively can adversely affect health.

Energy drinks are consumed as household beverages, but they may be unhealthy. Some people may notice their heart rate increase after taking energy drinks. Energy drinks can also cause unpleasant effects like stomach irritation, restlessness, anxiety, and trouble sleeping. 

One of the major constituents of energy drinks is caffeine. According to a review study, caffeine is presumably the most “frequently ingested pharmacologically active substance globally”.  

Also, according to the National Center for Complementary and Integrative Health, next to multivitamins, energy drinks are the most popular dietary supplements taken by American young adults and teens. The article noted that the group that consumes them most are males between the ages of 18 and 34. 

Still, experts believe that consuming a high amount of caffeine might not be healthy. Some common side effects of energy drinks include:

1. Caffeine overdose and addiction

One of the major concerns regarding the consumption of energy drinks is their caffeine constituents. Most energy drinks are loaded with caffeine. The amount of caffeine in energy drinks can range from 80mg to over 500mg. 

But, how much caffeine is too much?

Image by Caio Coelho on Unsplash

According to the FDA, 400 mg of caffeine per day is not generally associated with dangerous side effects. Depending on how sensitive people are to caffeine, taking more than that amount may be unhealthy. 

This means taking more than one bottle of energy drink in a day can lead to a caffeine overdose. Too much caffeine in the body can cause palpitations, hypertension, and calcium deficiency symptoms.  

Also, people who take energy drinks can get addicted to them due to their caffeine content. This means they might not function well if they do not take the drink. 

2. Increased anxiety

One of the possible side effects of taking energy drinks is increased anxiety. Because energy drinks contain a large quantity of caffeine, taking these beverages may induce anxiety in some people. 

A study of people with adenosine receptor gene polymorphism found a significant association between caffeine administration and anxiety.

3. Cardiac arrest

Another possible side effect of energy drinks is heart problems. When it comes to energy drinks, there is no standard amount that is safe for everyone. The amount of energy drink that is safe for an individual will depend on factors such as the person’s level of caffeine sensitivity, rate of caffeine metabolism, and health status. 

Someone with an underlying heart condition can go into cardiac arrest after taking a few energy drinks. A study showed a link between teenagers’ energy drink consumption and cardiac events.

Taking energy drinks can cause your heart to contract forcefully. It can also change the heart rhythm and cause the heart to beat faster. This can cause harm to people that have underlying heart conditions.

4. High blood pressure

Energy drinks can cause a spike in blood pressure. The caffeine contained in energy drinks is a vasoconstrictor. This means it reduces the size of blood vessels, increasing blood pressure. This is one of the side effects of energy drinks, as suggested by experts.

Energy drinks can cause a sudden, temporary increase in blood pressure in people who do not have hypertension. Research reported by the American Heart Association showed that young, healthy adults experienced significantly reduced blood vessel function after they consumed an energy drink. 

For people diagnosed with hypertension, taking caffeinated products like energy drinks can increase the risk of developing stroke and other heart-related problems. 

It would help to consume energy drinks in moderation. If you have an underlying heart condition, talk to your physician and find out if it is okay to take energy drinks. 

5. Weight gain

Aside from caffeine, energy drinks also contain added sugar. This means taking a high dose of caffeine can result in high blood sugar levels. One of the adverse effects of consuming too much added sugar is weight gain and obesity

Weight gain can also be linked to the development of type 2 diabetes. Clinicians believe that obesity is a promoter of type 2 diabetes, as many studies have suggested that being overweight or obese increases the risk of developing type 2 diabetes.

6. Mental health problems

Aside from increasing the risk of anxiety, taking energy drinks may lead to mental health issues or symptoms such as anxiety, jitteriness, and aggression. This is another possible side effect of energy drinks.

A 2018 study of energy drink use in U.S. service members after deployment published in Military Medicine showed a link between energy drink use and mental health problems, fatigue, and aggressive behaviors.

7. Vomiting and dehydration

Image by Andrea Piacquadio on Pexels

Taking too many energy drinks can cause an unsettling sensation in the stomach, which can lead to nausea and vomiting. Vomiting can lead to dehydration. This is one of the dangerous side effects of energy drinks.

Also, when you take too many energy drinks without drinking water, it can lead to dehydration. This is because energy drinks contain sodium too. 

A high sodium concentration leads to a sodium-water imbalance which can cause the body to pull water out of the cells and into the blood. This causes the cells of the body to become dehydrated. Drinking water will help balance the sodium-water ratio and will rehydrate the cells. 

Because energy drinks contain caffeine, which can be addictive, quitting their use may not be easy. However, quitting might benefit your health, especially if you have an underlying health condition. You might want to consider getting an expert’s help if you want to quit or notice it affects your health.  

When to seek medical attention

While beverage companies may tout the benefits of their products—like energy—you should always consume them with care. Before purchasing energy drinks, read the labels to learn about their ingredients. If you notice you experience discomforting symptoms, such as increased heart rate, unexplained anxiety, nausea, or vomiting after taking energy drinks, you should stop taking them.

If the symptoms persist even after you quit taking energy drinks, you may want to see your doctor. You may be experiencing symptoms of an underlying health condition, and seeing a doctor will ensure you get a proper diagnosis and treatment.


  1. Alsene, Karen et al. (2003). Association between A2a receptor gene polymorphisms and caffeine-induced anxiety.
  2. Golay, A, and J Ybarra. “Link between obesity and type 2 diabetes.” Best practice & research. Clinical endocrinology & metabolism vol. 19,4 (2005): 649-63.
  3. National Center for Complementary and Integrative Health. (2018 July). Energy drinks.
  4. Nawrot, P et al. (2003). Effects of caffeine on human health.
  5. Sanchis-Gomar, Fabian et al. (2015). Energy drink overconsumption in adolescents: implications for arrhythmias and other cardiovascular events.
  6. Toblin, Robin L et al. (2018). Energy Drink Use in US Service Members After Deployment: Associations With Mental Health Problems, Aggression, and Fatigue.
  7. US Food and Drug Administration (2018). Spilling the beans: How much caffeine is too much.