Caffeine vs WaterTeens
How Much Caffeine Can a Teenager Have? Limits by Weight, Plus Energy Drinks
How much caffeine can a teenager have? Health Canada says 2.5 mg/kg a day (125 mg at 50 kg); US pediatricians often say 100 mg. What it means for energy drinks.
The short answer
- Health Canada: teens should have no more than 2.5 mg of caffeine per kg of body weight a day. For a 50 kg (110 lb) teen, that's about 125 mg.
- US pediatric advice: many children's hospitals, citing the American Academy of Pediatrics, say ages 12–18 should keep to 100 mg a day or less, about one 8 oz cup of coffee.
- The AAP says energy drinks have no place in the diet of children and teens. Many cans have 150–300 mg, more than a teen's whole daily limit in one go.
- Adult limits (400 mg a day) don't apply to teenagers. Teens with heart conditions, anxiety or ADHD medication should check with a doctor.
Caffeine is part of teenage life now: iced coffee before school, a soda at lunch, an energy drink before practice or a late study session. So how much caffeine can a teenager have safely? Less than most people assume, and a lot less than a single large energy drink.
Here are the official limits, what they mean at different body weights, and how common drinks compare.
What the guidelines say about caffeine for teens
| Source | Teen guidance |
|---|---|
| Health Canada | Up to 2.5 mg per kg of body weight a day (under 18) |
| EFSA (EU) | Up to 3 mg per kg a day for children and adolescents is not a safety concern |
| US children's hospitals, citing the AAP | Ages 12–18: no more than 100 mg a day; no caffeine under 12 |
| American Academy of Pediatrics | Avoiding caffeine is the best choice for all kids; energy drinks have no place in their diet |
The limits differ because the evidence in teenagers is thin. A 2019 review in the Journal of the American Academy of Child and Adolescent Psychiatry noted that safety limits for young people are largely based on old data from adults. Its conclusion: typical, moderate caffeine use in children and adolescents appears relatively safe, but higher doses (over 400 mg) can cause physical, psychological and behavioral harm, especially in teens with psychiatric or heart conditions.
Health Canada adds that healthy older and heavier teens (14–18) "may be able to consume caffeine in a similar manner to healthy adults", but it keeps the 2.5 mg/kg figure as a precaution because the data in adolescents are limited. That's the one to use if you want a single number.
How much caffeine can a teenager have? Limits by weight
| Body weight | Health Canada (2.5 mg/kg) | EFSA (3 mg/kg) |
|---|---|---|
| 40 kg (88 lb) | 100 mg | 120 mg |
| 50 kg (110 lb) | 125 mg | 150 mg |
| 60 kg (132 lb) | 150 mg | 180 mg |
| 70 kg (154 lb) | 175 mg | 210 mg |
For most teens, that puts the daily ceiling somewhere between 100 and 175 mg. Compare that with the 400 mg limit for adults in how much caffeine is too much: a teen's allowance is roughly a third to a half of it.
Energy drinks for teenagers: why they're the problem
Coffee, tea and soda are hard to overdo by accident. Energy drinks are easy, because one can can hold more than a teen's whole daily limit and they're often drunk fast and cold.
| Drink | Size | Caffeine | vs a 100 mg teen limit |
|---|---|---|---|
| Coca-Cola | 12 oz (355 ml) | 34 mg | About a third |
| Black tea | 8 oz (240 ml) | 47 mg | About half |
| Mountain Dew | 12 oz (355 ml) | 54 mg | About half |
| Red Bull | 8.4 oz (250 ml) | 80 mg | Most of it |
| Drip coffee | 8 oz (240 ml) | 95 mg | All of it |
| Cold brew | 10 oz (300 ml) | 155 mg | 1.5× |
| Monster | 16 oz (473 ml) | 160 mg | 1.6× |
| Celsius | 12 oz (355 ml) | 200 mg | 2× |
| Prime Energy | 12 oz (355 ml) | 200 mg | 2× |
| Ghost Energy | 16 oz (473 ml) | 200 mg | 2× |
| Bang | 16 oz (473 ml) | 300 mg | 3× |
The AAP's clinical report on sports and energy drinks concluded that the caffeine and other stimulants in energy drinks "have no place in the diet of children and adolescents". The AAP's parent site, HealthyChildren.org, reports that caffeine-related emergency visits among middle and high school students nearly doubled between 2017 and 2023. For a brand-by-brand breakdown, see the energy drink caffeine comparison and how many energy drinks a day is safe.
Caffeine and teen sleep
Sleep is where caffeine does the most quiet damage. Teenagers already tend to fall asleep later, and school starts early. Caffeine has a half-life of about 5 hours, so a 200 mg energy drink at 4 pm still leaves about 100 mg in the body at 9 pm. That's enough to delay sleep and make it lighter, even if it doesn't feel that way. You can try the timing with the bedtime caffeine calculator.
That creates a loop: poor sleep, more caffeine the next morning, more caffeine after school, poor sleep again. The simplest fix is a cutoff: no caffeine after lunch, and no energy drinks at all. There's more on this in energy drinks and sleep and caffeine for studying, including why an all-nighter on caffeine tends to backfire.
Signs a teen is having too much caffeine
HealthyChildren.org lists these signs of too much caffeine:
- Fast or irregular heartbeat
- Raised blood pressure
- Rapid breathing
- Anxiety or restlessness
- Nausea
Headaches, irritability and tiredness when caffeine wears off are also common, and can be a sign of dependence (see caffeine withdrawal).
Get medical help straight away if a teen has a racing or irregular heartbeat, fast breathing, shaking, or can't sit still after caffeine, particularly after energy drinks or caffeine pills. Teens with a heart condition or anxiety, or who take stimulant medication for ADHD should talk to their doctor before having caffeine at all. If caffeine gives your teen a pounding or fluttering heart, see caffeine and heart palpitations.
Practical rules for parents and teens
- Keep it to about one coffee's worth a day (100 mg), or 2.5 mg per kg if you want a weight-based number.
- Skip energy drinks and caffeine pills. One can is usually over the limit.
- Stop by early afternoon on school days.
- Read labels. Caffeine is in iced tea, some sodas, pre-workouts, and coffee-flavored snacks.
- Swap, don't just ban. Decaf iced coffee, caffeine-free soda, or sparkling water keep the ritual without the stimulant.
Frequently asked questions
How much caffeine can a teenager have a day?
Health Canada advises no more than 2.5 mg per kg of body weight a day, about 125 mg for a 50 kg (110 lb) teen. Many US children's hospitals, citing the AAP, recommend no more than 100 mg a day for ages 12 to 18.
Can a 15-year-old drink energy drinks?
It's not recommended. The American Academy of Pediatrics says energy drinks have no place in the diet of children and adolescents. Many contain 150 to 300 mg of caffeine per can, more than a teen's daily limit.
Is one cup of coffee a day OK for a teenager?
For most healthy teens, one 8 oz cup of coffee (about 95 mg) fits within common limits. Have it in the morning, and check with a doctor if your teen has a heart condition, anxiety, or takes ADHD medication.
How much caffeine is too much for a 16-year-old?
More than about 2.5 mg per kg of body weight a day, which is roughly 150 mg for a 60 kg (132 lb) teen. A single large energy drink can be double that.
Is caffeine bad for teenagers?
Moderate amounts appear relatively safe for most healthy teens. The main risks are lost sleep, anxiety, and heart effects from high doses, which usually come from energy drinks, caffeine pills, or several drinks close together.
Sources
- Health Canada. Caffeine in foods.
- EFSA. Caffeine.
- American Academy of Pediatrics, Committee on Nutrition and Council on Sports Medicine and Fitness. Sports drinks and energy drinks for children and adolescents: are they appropriate? Pediatrics, 2011.
- HealthyChildren.org (AAP). The effects of caffeine on kids: a parent's guide.
- Seattle Children's. Why kids and teens should avoid energy drinks.
- Temple JL. Review: trends, safety, and recommendations for caffeine use in children and adolescents. J Am Acad Child Adolesc Psychiatry, 2019.
General wellness information, not medical advice. If you're pregnant, have a heart condition, or take medication that affects caffeine, check your limits with a doctor.