The Effects of Caffeine on Teenagers

It’s common for teens to reach for energy drinks before a soccer game or to turn to coffee to help them pull an all-night study session. But, drinking too much caffeine could be bad for a teen’s health.

Teenage girl drinking iced coffee through straw
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The American Academy of Pediatrics discourages caffeine intake for children and young adults. For most healthy adults, up to 400 mg of caffeine per day appears to be safe.

What Is Caffeine?

Caffeine is a drug that naturally occurs in the leaves and seeds of many plants. It’s also produced artificially and may be added to certain beverages and foods. Caffeine stimulates the central nervous system, causing increased alertness. Many people take it because they experience a temporary boost in energy and a slight elevation in mood.

Approximately 80% of the world’s population consumes caffeinated products every day, including roughly 73% of children. Although soft-drink consumption has declined in teens over the past decade, caffeine consumption in young people hasn’t changed. Teens are turning to coffee and energy drinks for caffeine.

Side Effects

Research on caffeine confirms that small doses of caffeine can enhance mood and alertness, increase information processing speed, awareness, attention, and reaction time. But most of the research has been conducted on adults, not children.

Caffeine can cause a number of unwanted side effects in both teens and adults. Some people are more sensitive to caffeine than others and just a small amount may produce unwanted effects. Here are the most common effects of caffeine consumption, according to the Diagnostic and Statistical Manual of Mental Disorders (DSM 5).

  • Insomnia
  • Restlessness
  • Nervousness
  • Excitement
  • Flushed face
  • Diuresis
  • Gastrointestinal disturbances
  • Muscle twitching
  • Rambling flow of thought and speech
  • Tachycardia or cardiac arrhythmia 
  • Periods of inexhaustibility
  • Psychomotor agitation

The effects of caffeine may begin only a few minutes after consuming it. Caffeine has a half-life of approximately five to six hours, which means it takes this long to reduce the concentration in your blood by half.

Health Consequences

Caffeine may stunt children’s development by disrupting the formation of key connections in the brain. During adolescence, when the brain has the most neural connections, caffeine may make the network less efficient.

A study in PLOS One found that young rats who consumed the rat-sized equivalent of the caffeine in three or four cups of coffee experienced reduced deep sleep and delayed brain development.

Since caffeine acts on the brain's reward-and-addiction center, it may also influence a child's food and beverage 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 10 milligrams of caffeine a 13-year-old boy consumes decreases his chances of getting 8.5 hours of sleep by 12%. Sleep deprivation 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 may also place a teen at a higher risk of developing osteoporosis.


Caffeine may also aggravate underlying health issues, like heart problems, and may also interact with certain medications or supplements.

Gender Differences

Researchers have found that caffeine affects boys and girls the same prior to puberty. After puberty, however, there are some gender differences in the way caffeine affects the body.

Overall, teen boys show a greater response to caffeine than teen girls. The heart rate in males decreases more in response to caffeine when compared to girls. Girls show greater increases in diastolic blood pressure than boys after being administered caffeine.

Researchers continue to evaluate the psychological factors, hormonal differences, and psychosocial factors that may account for the gender differences.

Caffeine Dependence in Teens

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

Regular caffeine drinkers may experience symptoms of withdrawal when they stop consuming it. Researchers have discovered children and teens may experience withdrawal after they’ve stopped consuming caffeine.

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)
  • Impairment in psychomotor and cognitive performances

Common Sources

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

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

While most people know coffee and certain soft drinks contain caffeine, there are some less obvious sources of caffeine parents and teens should be aware of, including:

  • 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)

Should Teens Consume Energy Drinks?

The American Academy of Pediatrics has taken a clear position on energy drinks—they have no place in the diets of children and adolescents.

A single energy drink could contain as much as 500 mg of caffeine, which is the equivalent of 14 cans of soda.

Despite the warning, approximately 50% of adolescents consume energy drinks and 31% consume caffeine on a regular basis. Some parents confuse energy drinks with sports drinks and many teens mistakenly believe energy drinks are healthy alternatives to soda.

Plus, energy drink companies create packaging and labels that appeal to a younger audience and frequently sponsor events (like snowboarding) that are likely to appeal to teens.

Energy drinks contain other substances that can be unhealthy for teens, including guarana, which is derived from a plant found in South America. Although it contains caffeine, it’s often not included in the caffeine tally.

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

Overdose and Toxicity

There have been reports of people—usually teens and young adults—overdosing on caffeine. The Substance Abuse and Mental Health Services Administration reports more than 13,000 emergency room visits in 2009 were associated with energy drinks.

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

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

Caffeine powder is usually marketed as a dietary supplement and it is not regulated by the FDA. It’s often available for purchase on the internet.

There have been several other deaths linked to caffeine overdose. An investigation by The New York Times in 2012 found at least 13 deaths linked to 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 take steps to encourage them to develop healthy habits and limit their caffeine consumption. Here are some steps you can take to educate your teen about caffeine and keep their consumption to a minimum.

Stock up Smartly

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

Educate Yourself

Nutrition labels don’t list how much caffeine a product contains, but it will be listed on the ingredient list. If you find the items your teen is consuming contain caffeine, a quick internet search will help you discover how many milligrams are in a food or beverage.

Talk About It

Many caffeinated beverages 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 sugar-sweetened teas aren’t good for her.

Talk to your teen about the dangers of caffeine in the same way you discuss drugs or alcohol. Warn your teen that consuming too much 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 believe stimulants are a normal part of adult life. And that could lead him 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 drink something with caffeine in it, make sure it’s early in the day.

Know the Warning Signs

Be on the lookout for signs that your teen is consuming a lot of caffeine. If your teen is jittery or having trouble sleeping, investigate what he’s 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 experience some unpleasant withdrawal symptoms if they suddenly quit caffeine altogether.

Frequently Asked Questions

  • Can caffeine stunt a teenager's growth?

    There's no evidence this is the case. Although caffeine affects calcium absorption, studies have not found negative effects of caffeine on bone growth. Similarly, sleep disruption associated with caffeine has not been found to affect growth (although inadequate sleep does have a lot of detrimental affects on kids of all ages).

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

    According to most children's health experts, children between 12 and 18 should ingest no more than 100 milligrams (mg) of caffeine each day—about the amount in:

    • One cup of coffee
    • One or two cups of tea (depending on how strong it is)
    • Two 12-ounce sodas
  • How can I tell if my teen is getting too much caffeine in their diet?

    A teen who ingests too much caffeine in a short amount of time may seem jittery or anxious, or have an upset stomach. Teens who are dependent on caffeine will show signs of withdrawal when they don't get enough caffeine, such as headaches. fatigue, irritability, and trouble concentrating.

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