The ad, for a product called Phosphagen HP, used the strapline: 'Think about the potential: 160% more energy, more power and more muscle than from regular creatine'.
The advertisers, SNC Ltd, cited findings from a study carried out by the Director of the Human Performance Laboratory at Creighton University but the authority considered it insufficient evidence to substantiate the claims.
However it welcomed action taken by the advertisers to seek advice from the Committee of Advertising Practice. The company has removed the claims from its catalogue.
Creatine, produced naturally by the body, has been shown to improve performance and muscle recovery in athletes. But a flood of creatine-containing products on the market, driven by significant activity from Asian producers, has caused tough competition in the sports nutrition sector, pushing manufacturers to find new competitive edge