Dosing system for adjusting a dose volume of a fluid medium, comprising a) a longitudinal center axis, b) a dosing sleeve with at least one communication opening for communicating with the surroundings, c) a dosing plunger, which can be displaced in the dosing sleeve in the direction of the longitudinal center axis between a retracted position and a depressed position in order to take up and dispense the medium through the at least one communication opening, characterized by d) a retraction limiting element to delimit a maximum retraction path of the dosing plunger in the direction of the longitudinal center axis, i) wherein the retraction limiting element can be axially fixed in at least one position to the dosing plunger, ii) wherein the retraction limiting element can be displaced radially to the longitudinal center axis between a radially inner position, axially fixed to the dosing plunger, and a radially outer position in relation to the dosing plunger, and iii) wherein in the radially outer position of the retraction limiting element, the dosing plunger can be displaced in relation to the dosing sleeve and the retraction limiting element in the direction of the longitudinal center axis, and iv) wherein the retraction limiting element in the inner position is entirely arranged inside the dosing sleeve, and e) an end stop arranged on the dosing sleeve for interacting with the retraction limiting element in the retracted position of the dosing plunger. a) a longitudinal center axis, b) a dosing sleeve with at least one communication opening for communicating with the surroundings, c) a dosing plunger, which can be displaced in the dosing sleeve in the direction of the longitudinal center axis between a retracted position and a depressed position in order to take up and dispense the medium through the at least one communication opening, characterized by d) a retraction limiting element to delimit a maximum retraction path of the dosing plunger in the direction of the longitudinal center axis, i) wherein the retraction limiting element can be axially fixed in at least one position to the dosing plunger, ii) wherein the retraction limiting element can be displaced radially to the longitudinal center axis between a radially inner position, axially fixed to the dosing plunger, and a radially outer position in relation to the dosing plunger, and iii) wherein in the radially outer position of the retraction limiting element, the dosing plunger can be displaced in relation to the dosing sleeve and the retraction limiting element in the direction of the longitudinal center axis, and iv) wherein the retraction limiting element in the inner position is entirely arranged inside the dosing sleeve, and i) wherein the retraction limiting element can be axially fixed in at least one position to the dosing plunger, ii) wherein the retraction limiting element can be displaced radially to the longitudinal center axis between a radially inner position, axially fixed to the dosing plunger, and a radially outer position in relation to the dosing plunger, and iii) wherein in the radially outer position of the retraction limiting element, the dosing plunger can be displaced in relation to the dosing sleeve and the retraction limiting element in the direction of the longitudinal center axis, and iv) wherein the retraction limiting element in the inner position is entirely arranged inside the dosing sleeve, and e) an end stop arranged on the dosing sleeve for interacting with the retraction limiting element in the retracted position of the dosing plunger.