The belief that drinking coffee or consuming caffeine will prevent a young person from reaching their full height is one of the most enduring health myths. For decades, parents have cautioned adolescents against caffeinated beverages, fearing interference with their physical development. This persistent notion often links caffeine directly to reduced final adult height. Determining whether this stimulant truly inhibits growth requires looking at the biological mechanisms of skeletal development and the specific effects of caffeine on a developing body.
The Scientific Consensus on Growth
Decades of research have consistently shown that typical caffeine consumption does not directly affect a person’s final height. Growth is primarily determined by genetics, with nutrition and overall health serving as supporting factors. Scientific investigations, including large-scale epidemiological studies, have failed to establish a causal relationship between moderate caffeine intake and stunted growth. The idea that caffeine somehow locks the growth plates—the areas of developing cartilage at the ends of long bones—is not supported by human data.
The origin of this long-standing myth likely stems from initial concerns about caffeine’s impact on bone health. Early studies suggested that caffeine could slightly increase calcium excretion through urine and mildly inhibit calcium absorption in the gut. Calcium is the primary mineral needed for bone strength and density. However, modern research confirms that this effect is minimal and temporary, especially when overall calcium intake is adequate.
A study tracking adolescent females aged 12 to 18 over six years found no difference in total body bone mineral gain or hip bone density across groups with varying levels of caffeine consumption. The findings indicated that even at the highest intake levels (up to 77 mg per day), caffeine did not correlate with reduced bone mass. Therefore, moderate consumption does not measurably interfere with bone growth or the ultimate determination of adult height.
How Caffeine Actually Impacts Development
While caffeine does not directly stunt growth, its physiological effects on developing bodies can pose other health concerns. As a central nervous system stimulant, caffeine profoundly impacts sleep patterns, which is where the indirect link to development arises. Quality, restorative sleep is the period when the body naturally releases the largest pulses of growth hormone.
Caffeine extends the time it takes to fall asleep and reduces the amount of time spent in deep, slow-wave sleep. By disrupting this cycle, excessive caffeine consumption, especially later in the day, can interfere with the body’s natural schedule for growth hormone release. This is not a direct stunting mechanism, but it significantly disrupts the overall healthy developmental process.
The stimulant properties of caffeine also affect the cardiovascular and nervous systems, which is more pronounced in younger individuals. Developing bodies are more sensitive to caffeine, resulting in symptoms like increased heart rate, elevated blood pressure, and “jitters.” High intake can trigger or exacerbate feelings of anxiety, particularly in those who are caffeine-naive or prone to stress.
Concerns about nutrient absorption remain, although the effect is small. Caffeine may slightly increase the excretion of calcium, a mineral rapidly deposited in bones during the pubertal growth spurt. For an adolescent with an already low-calcium diet, this mild diuretic effect could theoretically become more significant. However, the loss is so minimal that maintaining a balanced diet is generally sufficient to counteract it.
Establishing Healthy Caffeine Limits for Youth
Because of the negative effects on sleep, anxiety, and the cardiovascular system, major health organizations recommend strict limits on caffeine for young people. Pediatricians advise against any consumption of caffeinated beverages for children under 12 years old. This recommendation applies to all sources, including soda, tea, and coffee.
For adolescents between the ages of 12 and 18, the accepted safe upper limit is 100 milligrams (mg) of caffeine per day. This amount is roughly equivalent to a standard eight-ounce cup of home-brewed coffee or two twelve-ounce cans of caffeinated soda. Energy drinks are often a major source of excessive caffeine, sometimes containing two to three times the recommended daily limit in a single can.
To manage intake effectively, it is helpful to know the typical caffeine content of common beverages. An eight-ounce serving of black tea contains approximately 48 mg, while a twelve-ounce can of cola has around 35 mg. Adherence to the 100 mg limit ensures an adolescent avoids health risks associated with excessive consumption, such as sleep deprivation and increased anxiety. While caffeine will not inhibit growth, its overconsumption can impair overall health during this developmental period.