Methods and devices for micro-dosing a liquid are disclosed herein. According to one embodiment, a method for a time controlled micro-dosing of a liquid from a liquid reservoir includes: receiving the liquid reservoir with a structure wherein the structure is portable securing the liquid reservoir to the structure connecting a second end of a drive unit to a piston disposed within the liquid reservoir activating a drive motor displacing the drive unit with respect to the structure towards the piston in an axial direction with the drive motor moving the piston axially within the liquid reservoir and micro-dosing the liquid from the liquid reservoir.