The sale of energy drinks could be banned in England to anybody under 18, amid fears they are damaging children's health, the prime minister has said.
The government has launched a public consultation on its plans to make it illegal to sell the drinks to children.
Energy drinks contain high levels of sugar and caffeine and have been linked to obesity and other health issues.
The government is asking for views on what age the ban should apply to, but gave under 16 and under 18 as options.
Scotland, Northern Ireland and Wales have the power to implement their own bans.
UK youngsters are among the highest consumers of energy drinks in Europe, research has previously suggested.
The drinks contain high levels of sugar and caffeine, often more than those of standard soft drinks.
Excessive consumption has been linked to a range of health issues in children, from obesity, tooth decay, headaches and sleep problems to stomach aches and hyperactivity.
Surveys from teachers unions have also suggested that they contribute to poor behaviour in classrooms, although claims they can alter behaviour have been contested.
The ban would apply to drinks containing 150mg of caffeine or more per litre.
Many shops already have their own voluntary bans in place for under-16s, but it is still possible for children to buy the drinks from some retailers and vending machines.
Public Health Minister Steve Brine said: "We all have a responsibility to protect children from products that are damaging to their health and education, and we know that drinks packed to the brim with caffeine, and often sugar, are becoming a common fixture of their diet.
"Our children already consume 50% more of these drinks than our European counterparts, and teachers have made worrying links between energy drinks and poor behaviour in the classroom."
Food labelling laws already state that any soft drink with more than 150mg of caffeine per litre must carry a warning about its high caffeine content and are not recommended for children or pregnant or breastfeeding women.
Prime Minister Theresa May said: "Childhood obesity is one of the greatest health challenges this country faces, and that's why we are taking significant action to reduce the amounts of sugar consumed by young people and to help families make healthier choices.
"With thousands of young people regularly consuming energy drinks, often because they are sold at cheaper prices than soft drinks, we will consult on banning the sale of energy drinks to children.
"It is vital that we do all we can to make sure children have the best start in life and I encourage everyone to put forward their views."
What is in energy drinks?
Energy drinks contain high levels of caffeine, usually about 80mg in a 250ml can.
In comparison, a 330ml can of classic Coca-Cola contains 32mg and a can of Diet Coke 42mg.
Energy drinks also contain lots of sugar as well as other ingredients including vitamins and minerals or herbal substances.
Some smaller "energy shot" products can contain as much as 160mg of caffeine in a 60ml bottle.