A dosing mechanism for use with an injection device to adjust a dose to be discharged from the injection device, the dosing mechanism including an adjusting element which can be moved relative to the dosing mechanism and including a coupling element for being releaseably coupled to a threaded bar associated with the injection device such that the adjusting element can be moved relative to the bar in one direction while a relative movement in the opposite direction is prevented, the dosing mechanism further including a retaining element with an engaging element for preventing the bar from being rotated in at least one direction, and a releasing element for uncoupling the adjusting element and bar.