Energy Drink Side Effects

Energy drinks can have potential side effects if not consumed responsibly or as directed.

Energy Drinks

Because of the vast array of ingredients in Energy Drinks, it may make them more likely to produce side effects than beverages containing just caffeine alone.

What’s worse, the safety of energy drinks has become a major issue as consumption has increased among children and teens.1

Top 10 Energy Drink Side Effects

Recent research in Australia2 has highlighted the risks with over-consumption of energy drinks. This data was gathered from 7 years of calls to the Australian Poisons Center.

Listed in order of most common to least common:

  1. Palpitations / tachycardia
  2. Tremor / shaking
  3. Agitation / restlessness
  4. Gastrointestinal upset
  5. Chest pain/ischemia
  6. Dizziness/syncope
  7. Paresthesia (tingling or numbing of the skin)
  8. Insomnia
  9. Respiratory distress
  10. Headache

The Center for Food Safety Adverse Event Reporting System (CAERS) received over 140 complaints about adverse side effects from 5 Hour Energy, Monster, and Rockstar over the last 10 years. Some of these resulted in hospitalization and death. See the report here.

If you’ve experienced other energy drink side effects tell us about them in the comments below.

Energy drinks contain supplements, herbs, and vitamins and are required to list warnings on the label about consuming more than the recommended serving.


Potential Problems from the Specific Ingredients

In moderation most people will have no adverse, short-term side effects from drinking an energy drink, however, the long-term side effects of consuming energy drinks aren’t fully understood as of yet.

wean caffeine

However, if you have reached a state of dependence on energy drinks, then it’s time to start considering products specifically designed for helping you kick caffeine without withdrawal. Of those out there, we endorse Wean Caffeine which is highly effective and inexpensive.

Let’s take a look at the most common energy drink ingredients and list the potential side effects that could result from ingesting too much.


This is the most common energy drink ingredient and one of the most widely consumed substances in the world.

Caffeine tolerance varies between individuals, but for most people, a dose of over 400mg/day may produce some initial symptoms: restlessness, increased heartbeat, and insomnia.

Higher dosages can lead to:

  • Increased blood pressure
  • Heart palpitations
  • Anxiety and panic attacks
  • Gastrointestinal disturbance (diarrhea)
  • Increased urination
  • Dizziness, irritability, nausea, nervousness, jitters
  • Allergic reactions can include; rash, hives, itching, difficulty breathing, tightness in the chest, swelling of the (mouth, face, lips, or tongue), diarrhea, shakiness, trouble sleeping, vomiting
  • Headaches and severe fatigue from withdrawal
  • Painful withdrawal symptoms

(Read more about caffeine overdose here)

Caffeine can be found in other natural ingredients such as guarana,  green tea extract, and coffee extract or can go by many other names, so be aware of this when reading energy drink labels.

Please consult the caffeine database for an exhaustive list of caffeine in energy drinks (and other drinks). This is updated weekly.

Adrenal Fatigue

There is debate as to whether adrenal fatigue is a real disorder, but here’s what some think happens.

Some people can become tired even after consumption of caffeine. This is believed to be a symptom of adrenal fatigue where the body’s aadrenalinesystem has become overtaxed by the constant high caffeine intake.

The solution is not to increase caffeine even more – but to reduce, detox, and get the adrenal glands back to a healthy state.

Remember, it’s hard to pinpoint an exact safe dose because it varies from person to person and according to a person’s tolerance.

See our Caffeine Safe Dose Guide here.

Between 500 milligrams to 1000 milligrams in a 24 hour period will probably lead to some of the more severe side effects.

Click here to find out how much caffeine in different energy drinks would be deadly.


Most energy drinks are high in sugar in the form of high fructose corn syrup and/or cane sugar. Some use creative names to make their version of sugar seem “healthier”, like “natural cane juice”.

  • High sugar drinks are linked to the obesity.
  • Sugar causes tooth decay
  • Increases risk of type 2 diabetes.
  • The sugar in energy drinks causes blood sugar and insulin spikes, which later result in a “crash-like” feeling.
  • Sugar is also somewhat addictive.


No side effects from the Taurine3 in energy drinks have been documented.  Some countries (France, Denmark, and Norway) originally banned energy drinks because of their taurine content, but have since accepted that taurine consumption is safe based on the evidence to date.

The amount placed in energy drinks is well below what would be needed for therapeutic benefits or for any potential side-effects.

B Vitamins

  • More than 35mg of Niacin (B3) can cause flushing of the skin. Intake of 3000mg or more can result in liver toxicity. The British Journal of Medicine recently published a case study of a man who consumed about 5 energy drinks a day for a period of three weeks. This caused toxic levels of niacin to build up in his body, leading to nonviral hepatitis.  The unidentified energy drink in question supplied 200% of the RDA of B3. A summary is found here.
  • More than 100mg of B6 can cause sensory nerve problems (burning sensation) or skin lesions.


No major side effects have been reported, but it could cause dizziness, tiredness, headaches and an upset stomach. (src.) Ingesting large quantities has been linked to diarrhea. Large doses have been used to treat certain psychiatric disorders.


  • Some studies have linked it to sleeplessness, while others refute this.
  • Other possible symptoms include; low blood pressure, edema, palpitations, tachycardia, cerebral arteritis, vertigo, headache, insomnia, mania, vaginal bleeding, amenorrhea, fever, appetite suppression, pruritus, cholestatic hepatitis, mastalgia, euphoria, and miscarriage.


While no side effects have been reported, there’s still debate on its safety.4  Many countries including Canada, England, Germany, and France have concluded that it is not a safety concern.

Artificial Sweeteners

If you drink sugar-free energy drinks you may be consuming any number of artificial sweeteners. There is always debate around the negative health effects of these (particularly aspartame5).

However, all major health institutions regard them as safe.

Ginkgo Biloba

Gingko is a herb, and can cause some minor side effects in some people6:

  • nausea, diarrhea, headaches, dizziness, heart palpitations, and restlessness.
  • Can interact with other medication such as blood thinners and anti-depressants.
  • A recent study found that ginkgo caused thyroid cancer in rats.


Too much of this amino acid can cause vomiting, nausea, headache, diarrhea, stuffy nose, restlessness and sleeping difficulty.7


This amino acid is derived from green tea and many energy drinks and shots have begun putting “green tea extract” in their products.

It produces a different type of alertness than caffeine and there hasn’t been any scientific evidence of it causing adverse side effects. Some have reported feeling light-headed when consuming a dose of more than 300mg of L-Theanine.8

What is Safe For You?

Energy drinks probably shouldn’t be a staple of anyone’s diet and coffee is certainly a healthier source of caffeine.

However, despite a number of alarming reports of overdose in recent years, for most people energy drink consumption is fine in moderation.

Many reported side effects are anecdotal – being reported from patient’s records. So, it’s hard to say which ingredient actually caused the problems if the patient was ingesting several combinations of these at one time.

Be Careful of Pre-existing Conditions

If you or your child has a pre-existing heart condition of any sort – they should not be consuming energy drinks.

In general, it is better to avoid the larger drinks (i.e. Mega Monster has a massive 240mg caffeine in its 24 fl oz giant can) and stick to smaller 8oz cans.

If people drink energy products responsibly and use energy drinks occasionally, then most will likely avoid any of the energy drink side effects.

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  • Meranda

    I have experienced the breast shrinkage and it has caused me a lot of emotional pain. PLEASE DONT

  • Have you considered updating the side-effect info. Lots of stuff has been done in the past year and might be interesting to see if thoughts have changed over the year.

  • Dalton

    Never drink em! :@

  • Anjali

    My husband has been suffering from severe diarreah, restlessness, insomnia, burning feet, and fatigue. I just found this article. None of the docs he went to could figure out what was wrong with him. He is a welder/fabricator, and got into drinking a few of the most potent energy drinks, every day. Today he had to take the day off again because of these symptoms. I just found this article and wow am I happy to see that this could be the reason for his symptoms. He hasn’t had any energy drinks for two days, so he could be experiencing withdrawel. Be careful, vitamins and supplements in large doses can be poison!
    Good luck. and get more sleep.

  • Julian

    @ Misty, sounds like you mixed bad batches of alcohol with rockstar while eating fast food for 1 week straight. NOT ONLY the rockstar might be the one to blame but No sleeping + alcohol + Energy drinks + fast food = Death!! keep it up you might shorten your lifetime.

  • Robert Paulson

    I have lung cancer, and energy drinks have really helped me through the chemotherapy. True story.

  • oli

    you shuld not brink energy brinks theire dad

  • david

    i love energy drinks i drink alot of them

  • Chloe

    Hello there,I am doing an essay for language arts at university of Michigan, i would like to ask a question… is too much energy drinks consumed able to kill you? I have heard things and a young man has died from consuming too much energy drinks i would just like to take the time to ask you is it possible? do you think so? please reply to me asap. thank you very much. well appreciated. As Always, Chloe.

  • ted

    @Chloe, Water can kill you if you drink too much of it at one time and the same would be true for energy drinks as well. Just spend some time doing research and you’ll find a few cases of Energy Drink over-consumption but not many. Here’s an article I put together. Caffeine Overdose Fact or Fiction? Also you can search our site for other articles about people drinking too many Energy Drinks.

  • Angela

    When I drink monster, my face turns numb. I cannot pinpoint which ingredient causes this side effect, or if I’m just allergic to the whole drink. Can anyone answer my question?

  • Matt

    Thanks, this really helped my research project.

  • Plagio071305

    Energy drinks depends on the persons health because not all people experienced the same problem as the others.

  • sharon

    It appears that poople who consumed several energy drings per day had adverse effects. Would one dring a day be safe?

  • ted

    @sharon, the general rule of everything in moderation applies to energy drinks as well.

  • Pix

    Misty, do you think maybe the fact you’ve been drinking for 6 days straight and not sleeping and have only eaten a pita burger and poutine might have anything to do with you feeling like complete shit?

    P.S. Pissing blood IS NOT normal OR healthy! Perhaps before you blame it on energy drinks, you should get yourself to the nearest emergency room – fast.

  • dave

    my sister is 12 and she drinks energy drink religiously and it has caused extreme agressiveness in her………

  • I’ve tried just about every energy drink in moderation and I still have a crashing effect when they wear off. I have tried a NEW energy Drink called ADAPT and there are none of the jittery affects like with the others. It’s all natural ingredients.
    Info can be found on my site

  • what does it mean by 12% swedish citizenship? i myself have swedish citizenship but i never drink energy drink… so what do they mean by that? or is it a joke…?

  • hotty

    This is so stupid

Last Modified: November 10, 2017