Efficacy, providing a cosmetic effect, albeit reducing the appearance of wrinkles or hydrating the skin etc., is a key feature for cosmetic products. Claiming efficacy on the cosmetic pack or on the product’s website is an integral part of marketing the product. Promises are made about the results which can be achieved by using the product and, on the basis of that, consumers will want to buy the product. There are regulatory restrictions on cosmetic efficacy claims, though. These differ in different parts of the world and the regulatory texts are, in general, rather unclear. In essence, they say ‘you must not lie’. How are these regulations interpreted by the competent authorities? How does the cosmetic industry act within the framework of these regulations? How can it be made sure that the efficacy claims can withstand scrutiny? These are questions we get from our customers on a regular basis. This position paper was written to help the cosmetics producing industry in their judgment on how to go forward when wanting to make a cosmetic efficacy claim.