Expensive whitening toothpastes often do not contain bleaching agents and give no extra benefits, according to a study in Australia.
Consumer watchdog Choice says buyers are paying for marketing spin rather than benefits when purchasing higher-priced toothpaste.
It reviewed 17 toothpaste products ranging in price from A$1.27 to A$7.99 ($1.62 to $10.22) and broke down product claims such as "advanced-whitening", "multi-action", "enamel-lock", and "micro-cleaning crystals".
Choice found none of the whitening toothpastes investigated contained a bleaching agent required to alter the colour of teeth.
"These terms give the impression that the large range of toothpastes all do something different, with the expensive items doing something more than a basic product," said Choice representative Ingrid Just.
"In reality, you're paying extra for essentially the same product."
Most toothpaste products contain the same ingredients, such as fluoride, a mild abrasive such as calcium carbonate or hydrated silica, plus humectants to help the paste retain water.
Thickeners, sweeteners, lathering agents and flavours are added to enhance taste and appearance.
Choice said children's toothpaste products were also guilty of spin through the use of colourful packaging and cartoon characters.