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.

Get Help Quitting Caffeine

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  • ted

    @Just -Energy drinks have been in the US since 1997 but the ingredients used in energy drinks are nothing new and they have been studied and researched. They are fine in moderation as anything can be harmful in excess, for example too many coke’s a day are harmful, too many cookies a day are harmful, even too many carrots a day are harmful. To say that they are poison is being overly dramatic sorry. 🙂

  • Steve-O

    For a few years I was having one energy drink per day. I started having coffee in the morning and then I would still drink my energy drink later on. And even that was rare. But one day, I saw a documentary on the food and drinks we have and how we put junk into our bodies. So it made me think and stop having energy drinks. About a week after I stopped, I started having health issues that started out as just insomnia. I didn’t relate it at the time. Then a few days later, at night, I would wake up about 20 minutes after I fell asleep and had a feeling in my heart like it was weak. I would also wake up feeling VERY short of breath like my lungs were failing or something JUST as I would fall asleep. These symptoms went away after a while, until 2 days ago I went to a rock concert and they were giving out free energy drinks(trying not to mention brand names). I thought since I hadn’t had one in a long time, it would be okay. That night I slept fine, but the next day(last night) I had insomnia again. After some online research, I have determined that it is some kind of withdrawal form the energy drinks that’s causing my health problems. Also, the adrenaline rush that keeps me up at night with insomnia I believe to be adrinal fatigue. So personally, I suggest that energy drinks ARE far more dangerous than people think and should be given with a health warning!

  • on average, i might have 1-2 energy drinks a month. plus i drink alot of water and eat vegetables often. and eat home cooked meals. so yes, i am very healthy and responsible.

  • Candy

    My 22 year old son drank one Monster drink once or twice a week until three weeks ago. He was scheduled to work a night shift and go to an early college class the following morning. After class he had a late lunch with his father. He was feeling tired bought a Monster drink on the was home. Arrived home about 3:00 pm talked to me for about half hour went to his room was playing a video games with his younger brother and drank his Monster drink. Around 5:00 pm his brother yells “Something is wrong with Dale!” I ran it the room and he was having seizure, he face was blue and he was shaking all over; his back was arched, bitting his tomgue, hitting his head on the bed. (It was the scariest 5 minutes of my life.) 911 was called. His heart rate and blood pressure were high. He oxygen was low and he was placed on oxygen. He taken to emergency. Most of the test we negative, including a drug test. The only abnormal test was the blood sugar a little high from the sugars in the drink. The ER doctor asked if he drank a energy drink and he told them he drank one. The ER doctor and the nurse told me they had several cases of seizures related to energery drinks. (This has been his only seizure.) Called the Monster company, was told by Maria, “The can has a warning label do not drink more than three sixteen ounce cans in a day, or if caffeine sensitive, or pregnant”. The company feels it safe to drink and it is not responsible if someone has an adverse reaction. According to the company a seizure is not a side effect that is possible. He now has thousands in hospital bills that he has to pay (he does not have insurance) and it possibly could have cost him his life. He has not had another seizure since he stopped drinking the Monster drinks, he will not drink other energy drink because he is not sure they are as safe as they claim to be. Just be careful.

  • josh

    welli ussually have 1 red bull a day but i havent had side affects…and i only have 1 because if it makes you “smaller” down there…well thats just horrible

  • Sam

    Wow. It just hit me. I should stop drinking these. I almost died a few times. BP went through the roof. Be careful kids.

  • taz

    Hey:You all have good points, some even realizing they are going a little aver board,my first suggestion is if you have to drink an enrgy/d-1 a Day
    If you want an alternative revert to the first energy drink discovered; tea-green better yet-in closing the antioxidant factors counter the neg of the caffiene-you can drink up to 4 cups per day
    (be ready to P like a race horse though)

  • My heart beats very fast after drinking an energy drink, no matter how much caffeine was in the drink.

  • Namez

    I have like 3 a day! 😀

  • Mr.Rocket

    The acid in these will dehydrate you and induce vomiting before anything else,

    even if they do kill you what if they don’t? you get monthly bills a bitch of a wife and a squad of twerps that don’t respect you?

    drink up!

  • nurse

    you should be ashamed, there are kids out there who beleive that crap!

    energy drinks speed up your heart which will eventually damage it, esp at the rate you are drinking
    them. give it 5-6 years and then tell us again that they DO NOT cause heart problems.

  • ted

    Nurse? There’s not much evidence for that statement, in fact it has been shown through several well documented studies that people who drink 5 or more cups of coffee a day actually have better heart health and overall health. That’s a lot more caffeine then what’s in most energy drinks even drinking several a day.

  • i love monster, and am a huge fan of this drink…i started drinkin monster when i was 14…after read all the side effects..for me most of them sound familiar to the way i am and the side affects i have observed in my action. Although, the side afects are not as servere as i thought.i attempted withdrawl from this awesome yet mind diostorting drink. like D said, withdrawl is biach nd irritability and depression leads to suicide and kills too. i lov monster and will only drink it in moderation. monster liberates, cheers me up, and sends me flying..what iz better thean flying for ever with no worries of this world.

  • Nic

    How sad for all of you who think it is ok! If you take a regualr coke – place a nail in it for 4 days—go back and check the nail? These energy drinks have the caffeine AND all of these other harsh ingredients…drinking a MONSTER is like having 4 coke-colas. You can also pour coke on your battery that is corroded and it will clean it immediately. What do you think it is doing to your insides? And what about the sugars that are clotting arteries—YOUNG PEEPS OF TODAY–this is the first time any generation has been officially announced that you will NOT outlive your parents!! DID YOU HEAR THAT?
    Cooper Institute Certified Personal Trainer / Fitness Director

  • speedy

    i drank 1 mother. and after that. i couldnt stop Scarching. my body was going from cold to hot. i was dizzy i couldnt stand stright . and i couldnt think. at all. i was tired. after a few hours i couldnt stop shaking and feelings of being cold. Just Be careful how much u Drink maybe my body cant take it. but this is warning bells.

  • ted

    Thanks for your comment Nick, but I would have hoped that in your education to be a personal trainer you would have covered some basic biology and chemistry. i.e. sugar doesn’t clot arteries, also coke is made with phosphoric acid which is what reacts with the metal of the nail. A Monster has no phosphoric acid in it. No one would argue with the fact that energy drinks aren’t the healthiest thing to put in the body. Anything other than water isn’t optimal really, but to demonize energy drinks isn’t really accurate.

  • lol

    BOB !!! lol!! thats all i have to say

  • Ms.MonsterGirl


  • Xplaced

    Ha! Wow, moderation folks! If you say “I had 5 of these then 2 of those and I didn’t feel good!” then I completely understand. You shouldn’t feel good! You just over-did it a lot. 🙂

    I drink at the very, very most 2 energy drinks in a day and I haven’t done that in a couple years. I typically have 1 every other day, a Full Throttle at that. Sometimes a Monster Assault. But one a day is plenty guys, seriously. Especially if you drink any other caffeinated drinks too in a day like soda,coffee, or tea.

    You folks that complain after drinking 10 energy drinks and say “I don’t feel right”, well duh! No wonder you don’t feel right! Ha!

  • Hope

    I used to drink energy drinks like crazy while i was doing sports so i’d have more energy but i soon found out that they made me sick and have masive cramps! Now i barely ever drink them and only drink while im not doing sports. Now that i have read this article i will no longer be drinking any kind of energy drink again!

Last Modified: November 10, 2017