The invention relates to a drinking container comprising an interior (5) for accommodating a drinking liquid (14) and a container orifice (4) which is preferably located at the upper end and in which a closing mechanism (3) with a receiving chamber (9) is provided, the content of said receiving chamber (5) being introducible into the interior (5) of the container. The invention is characterized in that at least the top region of the closing mechanism (3) is equipped with an externally threaded part (6) forming a receiving chamber (9) along with a bottom covering area (7) and intermediate joining elements (8), the receiving chamber (9) being fitted with an inlet (22) at least in the bottom region. The content of the receiving chamber (9) can be released using a twisting-in process. The inventive drinking container is preferably used for preparing an unstable mixed beverage containing creatine powder (13) and an aqueous drinking solution (14).