LONDON (Reuters Life!) - An advert for pure silk pillowcases which claimed they had anti-aging qualities and made hair look beautiful was banned by Britain's Advertising Standards Agency (ASA) on Wednesday 21 October for being misleading.

The watchdog said the advert's claim that "after sun damage, the biggest cause of aging was from sleeping on cotton, linen or polyester pillowcases" could not be substantiated.

Neither was there evidence to support the advertiser's promise that the luxury silk pillowcases helped the skin retain moisture and minimize wrinkling, it added.

"Although some studies indicated that silk might be preferable to cotton to avoid sleep lines, we had not seen any studies which had sufficiently tested the effects of the silk pillows and connected it to the causes of aging," the ASA said, banning the advert from appearing again in its current form.

The ad's claims that sleeping on a pure silk pillowcase could also prevent "bed hair," frizz and split ends, repel house mites that commonly live in bedding and ease conditions such as eczema and asthma were also misleading, the ASA ruled.

It said that while the advertiser, Direct Beauty Products Ltd, had provided anecdotal evidence and journal articles to support its claims, it had not been able offer sufficient scientific proof.

(Reporting by Kylie MacLellan; Editing by Steve Addison)