When installing a recess can over the shower does it need to be placed on a (gfci) ground fault circuit interrupter circuit?
The short answer is no, it is not required. Your question implies that this is a new fixture being added. Therefore, you will not have to pull a wire all the way from the panel to the bathroom. The lighting is permitted to be on the same 20-amp branch circuit as the required branch circuit for the bathroom. Just make sure the GFCI branch circuit isn't connected to another bathroom or GFCI location. Otherwise, you will overload the circuit. Do not connect the new wire to the "load" side of a GFCI outlet either. If the outlet trips, you will be in the dark. Connect the wiring to the "line" side of an outlet or to a junction box in the ceiling.