Quick answer: No. There is no valid scientific evidence that coffee stunts growth, according to Harvard Health. A six-year study of girls aged 12 to 18 found caffeine intake made no difference to bone gain. Caffeine can disrupt sleep in children and teens, though, which is why health agencies still set lower caffeine limits for under-18s.
“Don’t drink coffee, it’ll stunt your growth” is one of the most repeated coffee myths. Here is where it came from, what the research shows, and how much caffeine is reasonable for kids and teens.
In this guide 5 sections
Does coffee stunt your growth?
No. Harvard Health says there is no scientifically valid evidence that coffee can stunt a person’s growth. It also points out that most growth happens before people drink coffee regularly: girls usually reach close to full height by 15 to 17, and boys a bit later.
The best direct evidence comes from the Penn State Young Women’s Health Study, which followed 81 girls from age 12 to 18 with six years of diet records. Girls who had the most caffeine gained just as much bone as those who had the least, and hip bone density at 18 was no different. The study did find that the low-caffeine group drank more milk.
Where did the “coffee makes you short” myth come from?
Harvard Health traces it to old studies suggesting coffee drinkers had a higher risk of osteoporosis, the bone-thinning condition that can lead to height loss through spinal fractures. Caffeine does increase calcium loss in urine slightly, but the effect is small, and the coffee–osteoporosis link was never confirmed. When researchers looked closer, people who drank more coffee also drank less milk, so low calcium and vitamin D intake, not coffee, was the likely problem.
Can caffeine affect sleep in children and teens?
Yes, and this is the real reason to go easy on caffeine when young. In a study of 191 US seventh- to ninth-graders, higher caffeine intake was linked with shorter night-time sleep, more time awake during the night and more daytime sleep. A 2025 FSANZ safety review notes that caffeine-related sleep loss may affect school performance and that paediatricians may recommend limiting caffeine for school-age children and teens and avoiding it within a few hours of bedtime. Sleep matters for growing children, so a late-afternoon coffee is the bigger concern than the coffee itself.
How much caffeine can kids and teens have?
Health Canada recommends no more than 2.5 mg of caffeine per kg of body weight a day for children and adolescents. FSANZ notes that EFSA and several other agencies use 3 mg per kg. Health Canada adds that healthy older and heavier teens (14–18) may be able to handle caffeine much like adults. At 2.5 mg per kg, that works out to:
| Body weight | Maximum caffeine per day (2.5 mg/kg) | About the same as |
|---|---|---|
| 20 kg (44 lb) | 50 mg | half an 8 oz cup of brewed coffee |
| 30 kg (66 lb) | 75 mg | three-quarters of a cup |
| 40 kg (88 lb) | 100 mg | one cup |
| 60 kg (132 lb) | 150 mg | one and a half cups |
Cup figures assume about 95 mg of caffeine per 8 oz cup of brewed coffee (USDA). Remember that cola, tea, energy drinks and chocolate count too. See how much caffeine is in coffee for other drinks.
Frequently asked questions
Can coffee make you shorter as an adult?
No. Adults can lose height with age, mainly from disc changes in the spine and from spinal fractures caused by osteoporosis, according to Harvard Health. Coffee doesn’t cause osteoporosis, and getting enough calcium and vitamin D addresses any small effect of caffeine on calcium.
Is it bad for a teenager to drink coffee?
Moderate amounts within the limits above aren’t known to affect growth. The main things to watch are sleep, total caffeine from all drinks, and sugar in sweet coffee drinks.
Does coffee affect bone health?
Harvard Health says the link between coffee and osteoporosis was never confirmed, and the Penn State study found no effect of caffeine on bone gain in teenage girls.
For more on coffee and health, see is coffee good for you? and how long coffee stays in your system.
This article is for general information and isn’t medical advice.
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