Teenagers may be causing long-term damage to their bodies and brains by binge drinking, research shows.
Binge drinking is a growing problem
Experiments on rats showed high doses of alcohol stunted their growth and impaired brain function.
The researchers, from the University of Memphis, say the findings suggest alcohol can be particularly damaging while the body is still developing.
Although the study was carried out on rats, they say teenagers should think twice before drinking to excess.
Lead researcher Dr Douglas Matthews said: "These findings suggest adolescence as a unique developmental period where exposure to high alcohol levels can produce changes in biological functions that might have long-lasting implications."
"Binge" drinking is defined as consuming five or more drinks in one session.
A study published last year found that up to a quarter of 13 and 14-year-olds in the UK claimed to have "downed" at least five alcoholic drinks in a single session.
The figure rose to half of all 15 and 16-year-olds.
And a report published in August by doctors working in A&E departments found that children as young as six have needed hospital treatment after going on drinking binges.
It is estimated that the amount of alcohol consumed by people under the age of 16 has more than doubled in the last 10 years.
The researchers gave 30-day-old immature rats enough alcohol to simulate what is known as chronic intermittent ethanol (CIE) exposure.
They found that the rats developed a high level of alcohol tolerance, which in some cases lasted into adulthood.
They also failed to put on weight at a normal rate, their livers showed signs of damage, and their brains appeared to be adversely affected.
Professor Linda Patia Spear, from the Centre for Developmental Psychobiology at Binghamton University, New York, said little was known about the long-term effects of alcohol consumption on teenagers.
However, she said a substantial number of studies had shown that the earlier individuals started using alcohol, the more likely they were to have alcohol-related problems in adulthood.
A government report suggests that the cost of alcohol abuse to the UK economy may be £20bn a year.
'Less able to cope'
Andrew McNeill, of the Institute of Alcohol Studies, told BBC News Online that previous research had linked binge drinking to brain damage.
He said: "There is good evidence that delaying the onset of regular drinking does not do you any harm, and an increasing amount of evidence that it may do you a lot of good."
A spokesman for the charity Alcohol Concern said: "It is well established that young people are less able to cope with the effects of alcohol, certainly in large amounts, than adults.
"Increased drinking among young people is an issue we would like to see addressed by the national alcohol strategy when it comes into force next year."
The research is published in the journal Alcoholism: Clinical & Experimental Research.