A guide rail for a window lifter for raising and lowering a window pane or door system for a vehicle door having a carrier and at least two guide rails disposed on the carrier. The guide rails comprise a guide profile that can be twisted or bent for guiding an adjusting part of the window lifter coupled to the window pane along an adjusting direction predetermined by the guide rails and the guide profile comprises a base and two legs protruding at obtuse draft angles from the ends of the base, such that the size of the draft angles is proportional to the bending or twisting of the guide rails prescribed by the kinematics of the retraction of the window pane over the adjusting travel of the window pane.