Are there really side effects from the ingredients in Energy Drinks?

Energy Drinks have become a major issue as people continue to consume more and more.

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

Top 10 Energy Drink Side Effects

Recent research in Australia 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 / ischaemia
  6. Dizziness / syncope
  7. Paraesthesia (tingling or numbing of the skin)
  8. Insomnia
  9. Respiratory distress
  10. Headache

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

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

Potential Problems from Specific Ingredients

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 of them from your favorite energy drink.


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 200-300mg may produce some initial symptoms: restlessness, increase heartbeat, insomnia.

Higher dosages can lead to more.

  • Increased blood pressure
  • Heart palpitations
  • Gastrointestinal disturbance (diarrhea)
  • Increase 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.
  • Headache and severe fatigue from withdrawal.
  • Breast shrinkage in females.
  • Painful withdrawal symptoms if not consumed.

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

Adrenal Fatigue

Some people can become tired after consumption of caffeine. This is a symptom of adrenal fatigue where the the body’s adrenalin system has become overtaxed by constant high caffeine intake. The answer 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 a safe dose because it varies from person to person and according to a person’s tolerance. Between 500 milligrams to 1000 milligrams in a 24 hour period will probably lead to some of the more severe side effects.


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” or they’ll call it “glucose”.

  • High sugar drinks are linked to the obesity epidemic
  • 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.


No side effects from Taurine 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 amounts placed in energy drinks are well below what would be needed for therapeutic benefit 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.
  • More than 100mg of B6 can cause sensory nerve problems (burning sensation) or skin lesions.


No known side effects have been reported, but 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. However 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 consuming any number of artificial sweeteners. There is always debate around the health effects of these (particularly aspartame) all major health institutions regard them as safe.

Ginkgo Biloba

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

  • 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.


  • vomiting, nausea, headache, diarrhea, stuffy nose, restlessness and sleeping difficulty.


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.

What is Safe For You?

Energy drinks should not be a staple. If you need caffeine then coffee is a healthier source.

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. 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 you drink responsibly and use energy drinks when you need a boost of energy and not use them as a replacement for water, then you most likely will avoid energy drink side effects.

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