About 90 percent of Americans consume caffeine in one product or another.
Caffeine is the world’s most popular stimulant. In moderate doses, it does no harm but actually may help people by decreasing the risk of several conditions.
Despite this, several myths about coffee abound. One of them is this:
Does caffeine stunt growth?
Is there truth to this? Or is this a mere urban legend?
The concern about coffee causing stunted growth goes back at least to the 16th century, when it was banned in Mecca, Saudi Arabia, for health reasons. King Charles of England banned coffee in 1675 for similar health concerns.
In more modern times, the hysteria over coffee goes back to C.W. Post of Post breakfast cereals and other foods, who also manufactured Postum, a grain-based drink for breakfast time.
Image from Smithsonian Magazine
Postum became popular and the advertising of it was aimed at parents who were told caffeine damages children. Postum was advertised as a coffee alternative without caffeine.
Mark Pregendergast wrote Uncommon Grounds: The History of Coffee and How It Transformed Our World. He told Smithsonian: 
“Postum made C.W. Post a fortune, and he became a millionaire from vilifying coffee, and saying how horrible it was for you. The Postum advertisers had all kinds of pseudoscientific reasons that you should stay away from coffee.”
Post ascribed kidney and heart dysfunction, nervousness and indigestion to coffee. He said it also led to sallow skin. Post died in 1914, but even thereafter ads for Postum said children should never be given coffee because it makes them sluggish, sleepless, irritable and robbed them of rosy cheek and sparkling eyes. Plus, the ads said, it hampers proper development and growth.
“To my knowledge, no one has ever turned up evidence that drinking coffee has any effect on how much children grow,” Pregenderast said.
Since then, parents have been reluctant to submit their children to drinking coffee every day.
Caffeine causing stunted growth may not necessarily be gospel truth for a variety of reasons:
Harvard Health tackles the question of caffeine and stunting and says: 
Whether or not coffee turns out to have significant health benefits, this popular beverage doesn’t stunt your growth. Your height is largely determined by the height of your parents and the quality of your diet and overall health while growing. If you eat a balanced diet and take measures to avoid osteoporosis, you’re likely to achieve the maximum height “allowed” by your genes. And, sorry: Just as drinking coffee won’t make you shorter, avoiding it won’t make you any taller.
Harvard says the belief held by some people that coffee stunts growth may come from a debunked claim that it causes osteoporosis or a decrease in bone mass or density. Osteoporosis can shorten people if there are compression fractures of the spine. But the fractures are what cause height loss, not the osteoporosis in and of itself. Still, osteoporosis does not routinely cause people to become shorter.
Years ago, some studies reported a heightened risk of osteoporosis among coffee drinkers. The studies said caffeine stimulates the body to eliminate calcium, which can be a factor in osteoporosis.
There was some alarm over this because millions of coffee drinkers could be at risk for calcium loss leading to osteoporosis. But the loss of calcium from caffeine consumption was small. Also, a link between osteoporosis and coffee was never substantiated.
Harvard Health reports:
In fact, when the studies suggesting a link were analyzed, it turned out that people who drank more coffee drank less milk and other calcium-containing beverages. So it was probably the dietary intake of calcium and vitamin D among coffee drinkers, not the coffee, that increased the risk of osteoporosis.
Harvard advises people who may have lingering uneasiness about calcium loss from coffee to take calcium and vitamin D supplements or to get them in their diets.
There is another fact that strikes down the coffee stunts growth idea: Most people attain their maximum height in their late teens, well before they start drinking coffee habitually.
There may be some link, but caffeine does NOT directly stunt growth.
The correlation, however, may be found in what caffeine does to your central nervous system and anxiety levels.
As a stimulant, caffeine affects the central nervous system. A cup or two a day would normally be okay but going beyond that would bring out caffeine’s bad side effects. Too many caffeinated drinks may cause jitters, anxiety, and dizziness, which could all mess up your normal sleeping patterns. And lack of quality sleep leads to stunted growth in the long-term, especially for children.
Aside for the above mentioned reasons, a number of studies have supported the claim that caffeine does NOT hinder you from getting taller:
We have good news for lovers of America’s two favorite mood-altering substances, caffeine and marijuana: Caffeine may enhance a pot smoker’s high.
The downside is that caffeine can also increase the chance of becoming addicted to cannabis.
If you often find yourself going to a room in your house only to forget what you’re meant to do, or talking about a movie character you’ve seen so many times but can’t remember the name of, then one thing is going on.
It’s so easy to dismiss these as simple moments of forgetfulness. But if this happens a lot, then it may be your body sending you a signal to do something and beat brain fog.
The writer, Dan Charles, bought a 4-ounce bag of caffeine and said it had as much caffeine as 1,000 tall Starbucks lattes. He said this caffeine was created in coffee beans on a hillside in the tropics. “Slowly and quietly, driven by the energy of sunlight, it formed inside coffee beans hanging on thousands of trees, most likely in Brazil or Vietnam,” Charles wrote.
“Those beans were harvested, loaded on ships bound for the port of Houston, Texas, and ended up at a factory within sight of downtown Houston: Atlantic Coffee Solutions. It’s owned by one of the world’s largest coffee traders, ECOM Agroindustrial Corp., which is based in Switzerland.”