Does Coffee Stunt Your Growth?

No, coffee does not stunt your growth, and neither does caffeine. Harvard Health says there is no scientifically valid evidence that coffee affects how tall you get, and pediatric endocrinologists agree. The real reasons for teens to go easy on caffeine are sleep, jitters and energy drinks, not height.

Does coffee stunt your growth?

Your adult height depends mostly on your genes, plus your nutrition, sleep and overall health while your growth plates are still open. Coffee isn't on that list. Cleveland Clinic quotes a pediatric endocrinologist who puts it simply: caffeine doesn't affect growth.

There is also a timing problem with the myth. Most growth happens before people start drinking coffee regularly. Girls usually reach close to their final height in their mid-teens, and boys a bit later.

Does caffeine stunt growth? What studies show

The idea that caffeine harms growing bones comes from calcium. Caffeine does make your body lose a bit more calcium in urine, but Harvard Health describes the effect as small.

When researchers checked this in teens, they found no harm. A Penn State study followed 81 girls from age 12 to 18 and tracked their caffeine intake for six years. Girls who had more caffeine did not build less bone, and their hip bone density at 18 was the same as girls who had very little.

What the study did find: the low-caffeine group drank more milk. That points to the real issue. If coffee, soda or energy drinks replace milk and other calcium-rich foods, you can miss nutrients your bones need. Teens aged 9 to 18 need about 1,300 mg of calcium a day (see does milk make you taller).

Where the "coffee stunts growth" myth came from

Nobody knows for sure. Harvard Health suggests it may trace back to an old belief that coffee causes osteoporosis (weak, thinning bones). Older studies seemed to link coffee and bone loss, but when the data were looked at again, coffee drinkers were also drinking less milk. The coffee-osteoporosis link was never confirmed.

Even if it had been, osteoporosis is mostly a problem of older adults, and it doesn't make young people stop growing.

How much caffeine can teens have?

There's no official federal milligram limit for teens, but pediatric groups give clear guidance:

• Ages 12 to 18: at most 100 mg of caffeine a day, according to guidance from the American Academy of Child and Adolescent Psychiatry (AACAP). That's about two 12-ounce cans of cola.
• Under 12: pediatricians advise against routine caffeine use.
• Adults: the FDA says about 400 mg a day is usually not linked to harmful effects in healthy adults. That number is not meant for teens.

Caffeine adds up fast. Here are the FDA's ranges for common drinks:

So a single large coffee or one energy drink can put a teen over the 100 mg guideline. Kids are also more sensitive to caffeine than adults, and the smaller you are, the less it takes to feel side effects.

Energy drinks: the bigger concern

Energy drinks don't stunt growth either, but they are the caffeine source pediatricians worry about most. The American Academy of Pediatrics (AAP) concluded that the caffeine and other stimulants in energy drinks have no place in the diets of children and teens. AACAP says pediatricians advise against any energy drink use for kids and teens.

Too much caffeine can cause a fast or pounding heartbeat, high blood pressure, anxiety, upset stomach, headaches and sleep problems. The FDA also warns that pure or highly concentrated caffeine powders and liquids are dangerous: about 1,200 mg taken quickly can cause seizures, and that is less than half a teaspoon of pure powder.

Caffeine and sleep: the real growth issue

This is where caffeine can matter for growing teens. Caffeine's effects can last up to 6 hours, so an afternoon coffee or energy drink can push bedtime later and make sleep lighter.

Growth hormone is released mainly during sleep. According to KidsHealth, one bad night won't stunt growth, but regularly getting too little sleep suppresses growth hormone and may affect growth over the long term. The CDC recommends 8 to 10 hours of sleep a night for teens aged 13 to 17. Read more in does sleep make you taller.

Bottom line: Coffee won't make you shorter. But if caffeine is costing you sleep or replacing milk and real meals, that's worth fixing while you're still growing.

Smart caffeine habits for teens

• Keep it to 100 mg a day or less, and count soda, tea and energy drinks too.
• Avoid caffeine in the afternoon and evening, since its effects can last up to 6 hours.
• Skip energy drinks and caffeine powders entirely.
• Don't let coffee or soda replace milk, water or meals. See foods that help you grow taller for what your body actually needs.
• If you drink a lot of caffeine now, cut back slowly. Stopping suddenly can cause headaches, tiredness and irritability.

When to see a doctor

Get medical help right away for chest pain, a racing or irregular heartbeat, fainting or a seizure after caffeine or an energy drink. Talk to a doctor if you have a heart condition, anxiety, or take ADHD medication, since stimulants can add up.

For growth itself, see a doctor if you haven't grown in a year, you're dropping across percentile lines on the growth chart, or you show no signs of puberty by about 14 (boys) or 13 (girls). Caffeine won't be the cause, but those signs deserve a checkup.

The takeaway

Coffee and caffeine don't stunt growth. Keep caffeine to about 100 mg a day, avoid energy drinks, protect your sleep and keep calcium-rich foods in your diet. Those habits help you reach the height your genes have planned for you.