Schoolchildren should be taught about the dangers of drinking too much caffeine in energy drinks, coke and coffee, say scientists.
They are the fastest-growing population of caffeine users with over eight-in-ten regularly drinking them and over a tenth (11.4 per cent) had at least one a day.
Only less than one in 20 never touched them.
It is is the most available and widely used psychoactive substance in the world and is the only drug legally accessible and socially acceptable for children and teenagers to take.
The Food Standards Agency advise that children should only consume caffeine in moderation while pregnant and breastfeeding women should not have more than 200mg of caffeine during the day - roughly two mugs of instant coffee or one mug of filter coffee.
A can of Coca-Cola has 32mg, a can of Diet Coke 42mg, a can of Red Bull 80mg but other energy drinks can contain as much as 500mg.
One of the most commonly reasons given by the teenagers was the perceived alertness the drink would give them helping with their school work.
While a little caffeine now and then probably won't harm a teen's health, consistent use could have negative consequences.
Too much can prevent them from getting the sleep and nutrients they need for healthy physical development.
And although small amounts of caffeine can sharpen mental focus, too much can have the opposite effect making them jittery and scatty.
Instead they should be offered alternatives to caffeine to increase energy - including eating a healthy diet and getting enough sleep.
Food and nutrition professor Dr Danielle Battram said: "Caffeine over-consumption and caffeine intoxication have serious health effects even in moderate doses.
"With that in mind we need to correct the misconceptions adolescents have regarding certain aspects of caffeine.
"By developing more comprehensive educational strategies and enhancing policies it may be possible to decrease caffeine use in adolescents and mitigate the potential health risks."
The Brescia University College in Ontario study of 166 youths - most aged 15 or 16 - found nearly half (44.6 per cent) drank caffeinated beverages one to six times per week.
Yet the number of adolescents aware of the negative health effects of caffeine was generally high.
The study published in the Journal of Nutrition Education and Behavior showed the teenagers perceived drinking the freely available beverages as a sign of being grown up.
What their parents drank, media and advertising, and social norms also contributed to how much they drink.
Yet caffeine can decrease a child's ability to perform tasks involving delicate muscular coordination, arithmetic skills or accurate timing.
Children under 12 are generally recommended to avoid caffeine or to limit its intake.
Caffeine is absorbed very quickly into the body and then passes into the central nervous system.
In low doses caffeine can affect the body causing decreased appetite, increased urination, hyperactive behaviour and difficulty sleeping.
More toxic effects such as nausea, vomiting, muscle cramps, twitching and agitation may occur when a child consumes more than 4.5 mg of caffeine per pound of body weight.
Severe caffeine toxicity can lead to fits, an increased heart rate and an irregular heartbeat or palpitations.