The Effects of Caffeine on Teenagers

From coffee and tea to energy drinks, caffeine is easy to find. Teens often reach for these drinks before a sports event or a long study session. And while it's true that caffeine may give them an energy boost or help them focus, drinking too much of it could be bad for their health.

This article discusses the short and long-term health effects that caffeine can have on teens. It includes the signs you should know that your teen drank too much caffeine and ways you can limit their intake.

Teenage girl drinking iced coffee through straw
Glasshouse Images / Getty Images

The American Academy of Pediatrics discourages children and young adults from drinking caffeine. For most healthy adults, up to 400mg of caffeine per day appears to be safe.

What Is Caffeine?

Caffeine comes from natural sources. It's in coffee beans, cacao (where chocolate comes from), tea leaves, and more. Manmade forms are also added to certain foods and drinks.

Caffeine is a type of drug known as a stimulant. This means that it excites the central nervous system, making the person who drinks it more alert. Many people find that caffeine gives them a temporary energy boost and can even brighten their mood.

An estimated 80% of people worldwide consume caffeinated products every day. This includes roughly 73% of children. Fewer teens are drinking soda compared to a decade ago. However, teens are still drinking plenty of caffeine, turning to coffee and energy drinks instead.

Side Effects

Research shows that small doses of caffeine can:

  • Enhance your mood
  • Make you more alert
  • Help you process information faster
  • Boost your awareness
  • Help you focus
  • Speed up your reaction time

That said, most of the research has focused on adults, not children. And not all research on caffeine shows positive side effects either.

Caffeine can cause a number of unwanted side effects in both teens and adults. Some people are more sensitive to caffeine than others. For these more sensitive people, just a small amount of caffeine may produce unwanted effects.

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM 5), the most common unwanted side effects of caffeine include:

  • Insomnia
  • Restlessness
  • Nervousness
  • Flushed face
  • Diuresis (increased urination)
  • Upset stomach
  • Muscle twitching
  • Rambling speech and thoughts
  • Tachycardia or cardiac arrhythmia (irregular heart rhythms)
  • Pacing, tapping toes, pulling at clothes, and other forms of psychomotor agitation

The effects of caffeine can start within a few minutes after you consume it. This drug has a half-life of around five to six hours. In other words, after you consume it, it takes five to six hours for there to be half as much caffeine in your blood.


Caffeine is a stimulant drug that excites the central nervous system. Drinking too much can make you nervous and restless. It can interrupt your sleep, cause muscle twitches, and even trigger arrhythmias. Some people are more sensitive to caffeine than others.

Health Consequences

Adolescence is a vital time for brain development. The brain has the most neural connections (synapses) during these years, and they will keep maturing well into your mid-twenties.

Research shows that drinking caffeine from a young age can stunt brain development. That's because caffeine can make these growing connections less efficient and stop them from forming.

Caffeine triggers pleasure circuits in the brain's reward system. It gives your brain a burst of dopamine (the happy hormone). This is the same process that leads to drug addiction.

It is thought that caffeine's effect on the brain's reward and addiction center may influence a child's food and drink preferences later in life.

Here are a few other ways that caffeine can impact teens and adolescents:


Caffeine takes a major toll on a teen’s sleep. Every 10mg of caffeine a 13-year-old boy consumes cuts his chances of getting 8.5 hours of sleep by 12%. Sleep deprivation (lack of sleep) in teens can affect their education, mental health, and physical health.


Caffeine may also cause the body to lose calcium. Consuming too much caffeine could lead to bone loss over time. Drinking soda or energy drinks instead of milk can also raise a teen's risk of osteoporosis down the line.


Caffeine may worsen underlying health issues, like heart problems. It can also interact with certain medicines or supplements.


Caffeine can have a negative effect on many parts of a teen's growing body. It can stunt their maturing brain and lead to bone loss. It can worsen other health conditions the teen may already have. It can also cause the teen to lose much-needed sleep, in turn affecting their overall health.

Gender Differences

Researchers have found that caffeine affects boys and girls the same prior to puberty. Once puberty passes, caffeine starts to affect males and females in different ways.

Overall, teen boys show a greater response to caffeine than teen girls. Girls are more likely to have a slower heart rate than boys after being given caffeine. Meanwhile, girls are more likely to have increased diastolic blood pressure. Diastolic blood pressure is the bottom number in a blood pressure reading. It stands for the amount of pressure in the arteries when the heart rests between beats.

Caffeine Dependence in Teens

Many people report feeling “addicted” to caffeine. They may have trouble quitting or cutting back on their caffeine intake. Some people continue consuming it even though they experience unwanted side effects.

Regular caffeine drinkers may have symptoms of withdrawal when they stop consuming it. Researchers have found that children and teens may go through withdrawal after they’ve cut out caffeine as well.

Withdrawal symptoms vary in severity. Common withdrawal symptoms include:

  • Headache
  • Fatigue
  • Sleepiness
  • Trouble concentrating
  • Difficulty completing tasks
  • Irritability
  • Depression
  • Anxiety
  • Flu-like symptoms (nausea/vomiting, muscles aches, hot and cold spells)
  • Impaired psychomotor and cognitive performance

Common Sources

Here are some of the most common sources of caffeine that appeal to teens:

  • Peach Snapple: 42mg (16 ounces)
  • Monster Energy Drink: 160mg (16 ounces)
  • Starbucks Frappuccino: 115mg (9.5 ounces)
  • Mountain Dew: 55mg (12 ounces)
  • Instant coffee: 31mg (1 tsp)
  • Brewed coffee: 95-200mg (8 ounces)
  • Iced tea: 70mg (12 ounces)

Most people know that coffee and certain soft drinks contain caffeine. But there are also some less obvious caffeine sources that parents and teens should know of, such as:

  • Dark chocolate: 18mg (1.45 ounces)
  • Clif Bar Peanut Toffee Buzz: 50mg (2.4 ounces)
  • Hot chocolate: 3-13mg (8 ounces)
  • Dannon All-Natural coffee yogurt: 30mg (6 ounces)
  • Vitamin Water Energy: 50mg (20 ounces)


People who drink caffeine regularly may go through withdrawal upon cutting it out. Caffeine is not just in coffee, tea, and energy drinks. It's in many less obvious food and drink items too, from protein bars to flavored yogurt. Read packages closely.

Should Teens Consume Energy Drinks?

The American Academy of Pediatrics has taken a clear stance on energy drinks: They have no place in the diets of children and adolescents.

A single energy drink could contain as much as 500mg of caffeine. This amounts to around 14 cans of soda.

Some parents confuse energy drinks with sports drinks. Many teens mistake energy drinks as being healthier than soda too.

It doesn't help that energy drinks are often marketed to youth. Companies that make these drinks often sponsor sports events that appeal to teens. Such events make it seem that energy drinks are a good choice for young athletes to drink.

Energy drinks contain other substances that can be unhealthy for teens. Some contain guarana, which comes from a plant found in South America. Although it contains caffeine, it's not often thought of as a caffeinated product.

Energy drinks can also contain amino acids, vitamins, and additives. The effects of these substances are largely unknown.

Overdose and Toxicity

Many teens and young adults have overdosed on caffeine. In 2009 alone, The Substance Abuse and Mental Health Services Administration reported more than 13,000 emergency room visits related to energy drinks.

Between 2007 and 2011, the number of energy drink-related visits to emergency departments doubled. In 2011, one in 10 of these visits resulted in hospitalization.

Caffeine toxicity can be fatal. Logan Stiner, a high school student from Ohio, had a cardiac arrhythmia and a seizure after using powdered caffeine. Doctors learned he took more than a teaspoon of the powder. This was 16 times the recommended dose.

Caffeine powder is usually sold as a dietary supplement, so the FDA does not regulate it. It can easily be bought on the internet.

Several other deaths have been linked to caffeine overdose. An investigation by The New York Times in 2012 found at least 13 deaths linked to energy drinks.


Ads and sponsored events can mislead teens into thinking energy drinks are safe and healthy. Caffeinated products, many of which are sold as supplements, can be bought online. Thousands of people go to the ER each year due to problems caused by energy drinks.

Limiting Caffeine for Teens

You can’t control all the things your teen chooses to eat and drink when you’re not around. But, you can teach them healthy habits and limit their caffeine intake. Here are some steps you can take to protect your teen from the dangers of caffeine:

Stock up Smartly

Don’t stock the fridge with soft drinks. Don’t buy teas, energy drinks, and other beverages with a lot of caffeine. Try to make it a habit for your family to drink water and low-fat milk instead.

Educate Yourself

Nutrition labels don’t list how much caffeine a product has. If you find that your teen is drinking caffeine, do a quick internet search for the product's ingredient list. This list will show how many milligrams are in the product.

Talk About It

Many caffeinated drinks contain a lot of sugar, which can contribute to obesity and tooth decay. So limiting caffeine could be better for your teen’s overall health. Make sure your teen knows that energy drinks and sugary teas aren’t good for them.

Talk to your teen about the dangers of caffeine in the same way you talk about drugs or alcohol. Warn your teen that too much caffeine could cause serious health problems.

Be a Good Role Model

If you turn to coffee to help you function, or you down an energy drink before you head out for a night on the town, your teen may grow to think stimulants are a normal part of adult life. And that could lead them to develop bad habits.

Limit Afternoon and Evening Caffeine

Drinking a Frappuccino after school or a soda after basketball practice could keep your teen up half the night. If they are going to have caffeine, make sure it’s early in the day.

Know the Warning Signs

Look out for signs that your teen is consuming a lot of caffeine. If your teen is jittery or not sleeping well, look into what they have been eating and drinking.

Help Your Teen Cut Back

If your teen regularly consumes more caffeine than they should, help them to cut back. Be aware they may have some unpleasant withdrawal symptoms if they suddenly quit caffeine altogether.


You can't control what your teen drinks when you're not with them. But you can set a good example, talk to them about the dangers of caffeine, and limit how much caffeine is in your home. Make sure you and your teen know the signs that they have had too much caffeine.


Caffeine is easy for teens to get ahold of. It's in coffee, tea, energy drinks, chocolate, and even protein bars. It's also sold online in powdered form, where it is often marketed as a supplement.

Caffeine overdose is a real risk for people of all ages. Educate your teen about the dangers of caffeine and be a good role model for them. Make sure your family knows the risks that caffeine poses, and the signs they have had too much.

Frequently Asked Questions

  • Can caffeine stunt a teenager's growth?

    Though caffeine affects calcium absorption, studies have not found evidence that it stunts bone growth. Lack of sleep due to caffeine has not been found to affect growth either.

  • How much caffeine per day is OK for a teenager?

    Most children's health experts agree that kids between 12 and 18 years of age should not have more than 100mg of caffeine each day. That roughly amounts to:

    • One cup of coffee
    • One or two cups of tea (depending on how strong it is)
    • Two 12-ounce sodas

A Word From Verywell

Replace your morning cup of coffee with a cold glass of lemon water to boost energy levels. Bump up the flavor by adding cucumber and ginger. Or, brainstorm healthy smoothies with your teen that they can drink before school or a sports event.

Sugar and caffeine may offer a quick burst of energy, but the come-down from them will have you reaching for more. A healthy diet and good sleep are more likely to keep you energized all day without the need for stimulants.

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Amy Morin, LCSW
Amy Morin, LCSW, is a psychotherapist, author of the bestselling book "13 Things Mentally Strong People Don't Do," and a highly sought-after speaker.