How many mg of caffeine should a teenager have

Written By: Andi Atkinson, UT Physicians | Updated: August 3, 2022

Whether it comes from coffee, energy drinks, soda, or tea, the majority of teens are probably sipping too much caffeine a little too often. Their choice of beverage has shifted from previous generations, but caffeinated beverages are more popular than ever.  

“Teenagers today consume less soda, but they’re taking in more caffeine from flavored coffees or energy drinks,” said Rebecca M. Beyda, MD, MS, adolescent medicine specialist with UT Physicians and assistant professor of pediatrics with McGovern Medical School at UTHealth Houston.

“Coffee and energy drinks have significantly more caffeine than soda, so it’s important to talk to your teens about caffeine and monitor the amount they drink, especially now as they return to school.”

Teens may reach for liquid caffeine to help wake up or give their brain a boost when they study. However, too much of this chemical can affect an adolescent’s physical and mental health. Mainly, high amounts can rob a young person of sleep and trigger negative side effects. 

“Teenagers need more sleep than adults because they’re growing, and most of them don’t even get eight hours. Because caffeine is a stimulant, high doses can reduce the amount of sleep they receive even more,” Beyda said. “Caffeine overload can also increase blood pressure, agitation, anxiety, and behavioral issues.”

Though it is all right for adults to gulp up to 400 milligrams of caffeine per day, it is drastically less for teens under age 17 because their bodies are more sensitive to the drug. For optimal growth and overall health, it is best to limit a teen’s consumption to 100 milligrams of caffeine a day — or less!

“We actually recommend zero caffeinated beverages and zero sweetened beverages to all our patients. Water is still the best drink for optimal health, and now there are flavored and sparkling waters to pick from,” she said. “However, if a teenager has already been introduced to caffeinated drinks, watch their consumption and teach them how to read the labels and find out how much caffeine is in the drinks they buy.”

According to the Food and Drug Administration, an 8-ounce cup of coffee contains between 80 to 100 milligrams of caffeine, while an 8-ounce energy drink can pack anywhere from 40 to 250 milligrams. Meanwhile, a 12-ounce can of soda holds 30 to 40 milligrams of caffeine and an 8-ounce cup of tea has 30 to 50 milligrams.

“Depending on what they prefer, teenagers can easily reach or exceed their caffeine limit with as little as one cup or can,” the doctor said.

Older teens can consume slightly more than 100 milligrams of caffeine depending on their height and weight, but it is still best to keep their caffeine tank very low.

“It’s important to remember most girls don’t stop growing until they’re 15, and most boys don’t stop until they’re 17,” Beyda said. “The teen years are also a time for them to develop healthy lifelong habits. Tell your teenager about caffeine because health is also part of their education.

“It’s also fine to have caffeinated drinks once in a while, as a treat. However, these drinks really should be the occasional, not the regular.”

Note: this article is an update from the original post in July 2016

Teenagers should consume no more than 100 milligrams of caffeine a day, according to recommendations from the American Academy of Pediatrics. Why? Consuming high amounts of caffeine can cause irritability, nervousness, rapid heartbeat and anxiety.

Here are five more reasons to help teens limit their daily caffeine intake:

1. Caffeinated drinks often contain empty calories.

Many caffeinated drinks also have lots of sugar and fat. Drinking too much soda may rob teens of valuable nutrients such as calcium.

“Even if you’re drinking tea or coffee, if you’re adding milk, sugar or honey, that can be a problem” with added calories and sugar, says Ty G. Bristol, MD, MPH, a pediatrician at UNC Pediatrics at Panther Creek.

2. Caffeinated drinks can cause dental problems.

Drinking coffee or tea can stain teeth. The sugar in many caffeinated beverages can lead to cavities.

3. Caffeine can cause insomnia.

Caffeine can make it hard to fall asleep at night, which could lead to insomnia and daytime sleepiness.

“Some teens can get twitchy, and caffeine can cause insomnia if you consume too much or late at night,” Dr. Bristol says.

4. Caffeine can affect your heart and head.

Large amounts of caffeine can raise blood pressure in some people.

“If you drink too much, especially those big energy drinks, they can increase your heart rate, and blood pressure goes up with caffeine,” Dr. Bristol says.

It also can cause withdrawal headaches.

“A kid that drinks too much caffeine chronically in high doses can develop a tolerance to it,” Dr. Bristol says. “And then, of course, if they try to stop, they can have withdrawal symptoms, which includes rebound headaches.”

5. Caffeine can drain your wallet.

Caffeinated beverages can be expensive, especially when you buy drinks from popular coffee chains. Think about how much money you could save if you didn’t spend so much on caffeine.

But if consumed in moderation, caffeine intake has benefits, too.

Here are three benefits of caffeine consumption for teens:

1. Caffeine can increase alertness and mental energy.

“Caffeine is a stimulant, and stimulants can help with attention issues,” Dr. Bristol says. “A little bit of coffee can help you be alert to give you a little bit of good mental energy.”

2. Caffeine in small doses can reduce headaches.

A small amount of caffeine may ease headaches. Before a headache, blood vessels tend to enlarge, but caffeine has properties that cause the blood vessels to narrow and restrict blood flow, which can help reduce head pain.

“Caffeine is actually used in some of the headache medicines,” Dr. Bristol says.

3. Caffeine can help you poop.

Drinking coffee can stimulate movement of the muscles in your colon that cause bowel movements.

“There are some studies that say a little bit of caffeine can actually help with constipation because of how it affects the colonic muscle,” Dr. Bristol says.

So Should Your Teen Drink Caffeine?

It’s important to know how much caffeine is in your teen’s drinks.

“Too much of anything is not a good thing,” Dr. Bristol says. “The key is moderation.”

Dr. Bristol also says never to mix caffeine with drugs or alcohol.

“Whether it’s illicit drugs or alcohol, you may be compounding the side effects of those things,” he says.

Think your teen may be drinking too much caffeine? Talk to your doctor, or find one near you.

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