Children as young as eleven are taking potentially harmful steroids in an attempt to enhance their body image.
The shocking claim came from Prof Les Iversen, the chairman of the Advisory Council on the Misuse of Drugs (ACMD).
It came as the ACMD called for a ban on internet sales of the drugs and amidst increasing concern over the sexualisation of children.
Earlier this year a Government report warned that exposure to an increasing amount of "hyper-sexualised" images by the media was selling young people the idea that they have to look "sexy" and "hot".
Now The Daily Telegraph reports more than 6,000 children aged between eleven and 15 admit to regularly taking the steroids.
Prof Iversen said: "Surveys of young people indicate that a small, but significant, number of 11-15 year olds take anabolic steroids.
"This is particularly worrying because steroid use could interfere with their normal growth and sexual development. It is possible that young users are motivated by the same considerations as older people, namely a desire to enhance 'body image'."
Anabolic steroids are Class C drugs and it is illegal to possess or import them with intent to supply, although it is legal to own them as a medicinal product for personal use.
In 2007, the ACMD said young boys were taking steroids because they "want to be in boy bands and attract girls". This was despite warnings that taking the drugs can cause sterility.
The advisers have recommended that import regulations be amended which would effectively make sales over the internet illegal.
James Brokenshire, the crime prevention minister, said: "Abuse of anabolic steroids is harmful. We are committed to stopping the unlawful supply and use of these dangerous substances, which can cause serious psychiatric and physical problems.
"We will carefully review the recommendations set out in this report and respond shortly."