A leaflet contravened advertising rules by promising a comprehensive health check on the basis of CT scanning technology, a watchdog said.
The circular for Lifescan claimed it had given thousands of people "peace of mind" after they underwent the private scan and assessment, adding: "The images are so detailed, our consultant radiologists can tell how well your body is functioning.
"They can also check for early signs of a range of illnesses, including heart disease, lung cancer, colon cancer, aneurysms or osteoporosis, even before there are any symptoms ..."
A doctor complained that the advert was misleading and irresponsible because it could discourage patients from seeing their GP, and implied that a CT scan could identify any problem. It also failed to make clear that the radiation from CT scans could be harmful if used frequently.
Upholding the complaint, the Advertising Standards Authority (ASA) noted that current advice recommended against CT scanning for screening people without symptoms unless it was part of a national screening programme.
The ASA said the leaflet's wording suggested that a Lifescan CT scan would identify any kind of health problem and said it must not appear again in its current form.
Defending the ad, Lifescan said they did not believe the circular discouraged recipients from seeing their GP or that it implied every type of health problem would be identified.