Cosmetics firm Avon has been criticised over a mascara advert which featured a model wearing false eye lashes.
Customers complained that a catalogue model promoting the company's Bright Eye Duo product had false lashes on.
The Advertising Standards Authority (ASA) ruled Avon should not have said the mascara-and-eyeshadow product made lashes "appear 65% longer".
Avon said wearing false lashes in ads was a "global standard technique" which customers were aware of.
The company also said research backed its "65%" claim.
However, the ASA told Avon to remove the claim from future marketing of the product and also include a disclaimer in future advertisements for any mascara product that featured models wearing false lashes.
The ASA made a similar criticism in July, over a L'Oreal TV advert in which actress Penelope Cruz also wore false lashes.
Of the Avon advert, the advertising watchdog said: "We considered that readers would expect the effect of the mascara displayed in the ad to be achievable by most users.
"We understood, however, that that was only likely to be the case if the user simultaneously wore false lashes.
"Because the ad did not make clear that the model wore false lashes, we considered that readers could infer that the same effect could be achieved as a result of the product's application to natural lashes."
The ASA concluded that "in the absence of a disclaimer stating that the model wore a false set of lashes, the ad exaggerated the effects achievable from using the product and was likely to mislead".
An Avon spokeswoman said there was no intention to mislead customers.
"However, we respect the ASA's opinion and will remove the claim that 'lashes appear up to 65% longer' and include a disclaimer in future advertisements for any mascara product that features models wearing false lashes," she said.