A method for preparing a dairy product in a production line, includes a step of continuously injecting at least one sterol and/or stanol ester through the production line at a predetermined temperature T1 no lower than the melting point of the ester, and particularly at a temperature of 35-80° C., and into a dairy composition at a predetermined temperature T2 no lower than the temperature T1, which composition consists of an initial emulsifier-free milk-based composition containing milk proteins, to give a mixture, wherein the step of injecting at least one sterol and/or stanol ester is carried out before a step of homogenizing the mixture.