Caffeine and energy drinks

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Caffeine is a stimulant drug found in many drinks, treats and some medicines. Find out its effects on your body and how much of it is OK to consume per day.

Key points

  • Caffeine is a drug that can be found in coffee, tea, cola drinks, energy drinks, chocolate and some medicines.
  • Caffeine is a stimulant, which is a drug that can make you feel more awake, alert, confident or energetic.
  • It is not recommended to have more than 2.5 mg of caffeine per kilogram (kg) of body weight per day if you are a teen 13 years of age or older.
  • The effects of caffeine on your body depend on the amount you consume, but everyone’s reaction is different. You should limit how much caffeine you have when possible, as it can cause dehydration and affect your sleep and heart rate.

What is caffeine?

Caffeine is a stimulant drug, which is a drug that can make you feel more awake, alert, confident or energetic. It can be found in coffee, tea, cola drinks, energy drinks, chocolate and certain medicine. You may find yourself reaching for foods and drinks that contain caffeine to help you study, prepare for a big game, or have fun during a party. While it's true that caffeine can give you an energy boost or help you focus, drinking too much can have a negative effect on your health. Caffeine can help you feel more alert and less tired; but for some people, too much caffeine can affect their sleep and cause vomiting, heart palpitations, diarrhea, agitation, and other types of unwanted effects. Instead of having large amounts of caffeine, consider healthy nutrition, quality sleep, and regular exercise to keep you energized all day.

Where can you find it?

The main sources of caffeine are soft drinks, coffee drinks and energy drinks; but caffeine can also be found in tea, chocolate and other foods.

Examples of some of the most common sources of caffeine include:

Brewed coffee95-200 mg (8 oz/237 ml)
Monster Energy Drink160 mg (16 oz/473 ml)
Starbucks Frappuccino115 mg (9.5 oz/281 ml)
Red Bull Energy drink80 mg (8.3 oz/245 ml)
Iced tea70 mg (12 oz/355 ml)
Mountain Dew55 mg (12 oz/355 ml)
Vitamin Water Energy50 mg (20 oz/591 ml)
Clif Bar Peanut Toffee Buzz50 mg (2.4 oz/71 ml)
Diet Coke45 mg (12 oz/355 ml)
Peach Snapple42 mg (16 oz/473 ml)
Pepsi38 mg (12 oz/355 ml)
Coke34 mg (12 oz/355 ml)
Instant coffee31 mg (1 teaspoon)
Dark chocolate18 mg (1.45 oz/43 ml)
Hot chocolate3-13 mg (8 oz/237 ml)

What are the effects of caffeine on the body?

Small amounts of caffeine can make you more alert, help you focus, boost your mood and awareness, and speed up your reaction time. However, caffeine can also have some unwanted effects. The most common include:

  • increased or irregular heartbeat
  • trouble sleeping
  • nervousness
  • restlessness
  • muscle twitching
  • upset stomach
  • increased urination
  • anxiety
  • diarrhea
  • dehydration

The effects of caffeine can begin a few minutes after consuming it, and usually last for up to 6 hours.

Which dose is recommended?

For teens ages 13 and over, it is not recommended to have more than 2.5 mg of caffeine per kilogram of body weight per day.

Example body weight (kg/lbs)Limit of caffeine (mg/day)
50 kg/110 lbs125 mg
60 kg/132 lbs150 mg
70 kg/154 lbs175 mg
80 kg/176 lbs200 mg
90 kg/198 lbs225 mg
100 kg/220 lbs250 mg
110 kg/243 lbs275 mg

For example, if you 15 years old and weigh 56 kg, your recommended daily allowance of caffeine is 140 mg. If you have three 8 oz cups of coffee a day, you would be drinking approximately 145-460 mg of caffeine over the recommended limit.

Energy drinks

Energy drinks (not to be confused with sports drinks) are not recommended at all for children or teens because of their high levels of caffeine, and other ingredients. It is possible that even just one energy drink can have more caffeine than your safe daily amount. Some of the unwanted effects of energy drinks include:

  • Dehydration
  • Irregular heartbeat
  • Trouble sleeping
  • Feeling nervous or jittery

If you are going to consume energy drinks, it is important to drink them in moderation and carefully read the label and follow any instructions. It can be dangerous to drink energy drinks on an empty stomach, and they should not replace food. It can also be dangerous to mix energy drinks with alcohol.

What are the risks of having too much caffeine?

Caffeine can have more than twice the impact on your body than it does on an adult’s, depending on your body weight. This means you are more likely to develop caffeine-related symptoms. Some people are more sensitive to caffeine than others. If you are sensitive to caffeine, just a small amount can have unwanted effects. In the long term, consuming too much caffeine can cause your body to lose calcium, resulting in weak bones (osteoporosis).

If you have too much caffeine in a short amount of time, it can cause overdose and toxicity. This is particularly common when consuming energy drinks. Symptoms of caffeine overdose can including vomiting, high blood pressure, irregular or racing heartbeat, disorientation, and seizures.

People can become dependent or addicted to caffeine. Those who feel “addicted” to caffeine may have trouble quitting or cutting back on their caffeine intake. Some people continue consuming it even though they experience unwanted side effects. Common withdrawal symptoms can include:

  • headache
  • trouble concentrating
  • sleepiness
  • fatigue
  • irritability
  • difficulty completing tasks and problem solving
  • difficulty with coordination and balance

What can you do to limit caffeine intake?

Before abruptly stopping consuming caffeine, it is important to identify if you have already developed a dependency. Dependency can feel like you can’t function or start your day without having caffeine, and you might feel jittery and have difficulty sleeping. If you are dependent on caffeine, try removing it from your diet gradually to avoid withdrawal symptoms.

There are many coffee alternatives that will provide you with adequate energy. For example, replace your morning cup of coffee with a healthy smoothie; before a sports event, drink plenty of water.

Limiting your caffeine in the afternoon and evening can also help you manage your caffeine consumption. Drinking caffeine in the early morning instead of in the evening can provide a boost in energy that can carry over the entire day and allow you to fall asleep comfortably at night.

It is also helpful to do a bit of research before consuming caffeinated products. Nutrition labels don’t list the amount of caffeine a product has, so you may want to do a quick search for the product's ingredient list on the company’s website. This list will show you how much caffeine the product contains.

Although caffeine can temporarily make you feel more awake, alert, confident or energetic, a healthy diet, exercise and good sleep are more likely to keep you energized all day without the need for stimulants.

Last updated: May 2nd 2022