A teenage boy died in the US after drinking three caffeinated drinks in less than two hours.

South Carolina student Davis Cripe had drunk a large fizzy drink, a latte and an energy drink in the two hours before he collapsed.

Speaking on High Noon, Professor Niall Moynan said there's little to no evidence that increased caffeine consumption improves performance.

"For teenagers and children, they should be consuming as little caffeine as possible in a developing heart," he said. "They don't know how their body is going to react because they're still so young.

"You're consuming these adults doses that weren't designed for children or adolescents in the first place."

The recommended daily allowance of caffeine for a child is 50mg a day, and under 100mg for a teenager. For adults, it's recommended that they consume under 500mg.

On average, a cup of tea is 44mg. Some brands of energy drinks contain between 100mg to 250mg.

A marketing issue?

"Caffeine is a stimulant. It's not all bad. But they're accessible to kids. They're stored near soft drinks and now children think they're better than soft drinks," he continued.

"It's a marketing issue, and it's a parental issue and it's an education issue. If it's over-consumed in people who are vulnerable, it can cause sudden cardiac death or other cardiac events."

Dr Moynan said the supplement industry is massively unregulated, citing the sponsorship of sports events and athletes as encouraging the practice among young people.

"The whole thing now is, it's cool to take these energy drinks [...] This is a lifestyle choice where people make the decision to consume these high energy drinks."