The advertising watchdog has banned a campaign for the Size Zero Pill that promised users it would "make your body lose so much weight your closest friends won't recognise you".

Lipo-Slim Laboratories' direct mail campaign had dozens of statements relating to the alleged weight loss capabilities of the pill.

Claims included a guarantee of "24-180lbs of weight loss", the ability to lose "12 pounds with just 5 capsules", or a 20-pill course chosen by "most users ... as they wanted to lose 48 pounds in just 20 days – it's so easy".

"No matter what you eat or how often, no matter what, you won't be able to stop losing weight," the Size Zero Pill marketing proclaimed. The marketing featured two testimonials, including the tale of Jemima who lost 149lbs in 12 weeks.

The Advertising Standards Authority investigated the campaign on seven points, including whether the claim that the pills were "completely safe with no side effects" was misleading and could be substantiated and whether it was irresponsible.

Other things investigated by the ASA were whether the testimonials and "before and after" pictures were genuine; whether claims that the pills were "safe and natural" and had been "rigorous independently monitored test after test" could be substantiated and whether the ad made medicinal claims for an unlicensed product.

On all seven issues the ASA concluded that the company was not able to substantiate its claims.

The ASA also said that the advertising promoted an unhealthy rate of weight loss because the advertising code stated that "for those who were normally overweight, a rate of weight loss greater than 2lbs per week was unlikely to be compatible with good medical and nutritional practice".

Lipo-Slim Laboratories said that in light of the complaint to the ASA it had ceased advertising the Size Zero Pill, and would not undertake anymore marketing until its claims were rewritten in a form that complied with the regulator's advertising code.

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