Adverts for the Pink Patch claimed dieters could lose up to a stone in two weeks just by wearing the pink patch, which according to the company, reduces cravings by releasing herbal ingredients into the body.
However, advertising watchdog the ASA said the advert was "irresponsible" and promoted "bad medical practice".
According to the ASA, there was no evidence that the ingredients resulted in any weight loss. It also highlighted that some of the studies for the patch were carried out on animals, not humans, which is contrary to the ASA code.
Olivia Campbell, spokeswoman for the ASA, said: "The ad was irresponsible for promoting bad medical practice of losing a stone in two weeks and failed to provide persuasive scientific evidence to substantiate its claims."
Nobody from CYC Marketing, the company behind the advert, was available for comment on the judgment.