Government advisers have said that people could be putting themselves at risk if they have body scans that use radiation.
And the Committee on Medical Aspects of Radiation in the Environment (Comare) said that private firms catering for the "worried well" should stop offering full body scans and should be regulated by the Department of Health.
The group said that anyone with symptoms who turned up seeking a private scan should be sent to see their GP instead, while firms should be forced to provide standardised information to patients seeking the X-rays, which are known as computed tomography (CT) scans.
Comare's report said people may actually increase their risk of developing cancer by undergoing unnecessary scans, which can also detect "abnormalities" that are in fact harmless – known as false positives.
Chief Medical Officer Sir Liam Donaldson said: "We welcome this comprehensive and informative report, which we asked Comare to undertake in 2006.
"We will be consulting immediately on how best to respond to its recommendations and we will be taking the views of the public and healthcare professionals into account as part of this process."