Caffeine consumption among US teenagers (13–17y), young adults (18–24y) and adults (25–29y) for a 10 year period was examined using NHANES 2003–12. Of the 85% who consume caffeine 84% consume caffeinated beverages. This percentage remained constant despite new caffeine sources. Less than 7.1% of the population consume energy drinks. While mean caffeine intake among teenage caffeine consumers decreased from 62 to 55�mg/day (p-value�=�0.018) over the 10-year period, no discernable trend was observed for other age groups. Caffeine intake from energy drinks increased, and was only statistically significant for age 18–24y accounting for <9% of total caffeine intake. Mean caffeine intake per consumption occasion was equivalent between coffee and energy drinks for teenagers and young adults. During a 30-min period mean caffeine consumption was similar when an energy drink was the only consumption event or when it occurred with other caffeinated beverage products suggestive of a substitution effect. Linear regression models of caffeine intake from energy drinks against caffeine from coffee, tea and soda among energy drink consumers in the upper 50th percentile shows a statistically significant inverse relationship (R2�=�28%, coffee: β�=�−0.35, p�<�0.001; tea: β�=�−0.44, p�<�0.001; soda: β�=�−0.22, p�=�0.036) and further supports the substitution concept.