An electric submersible pump (ESP) assembly. The ESP assembly comprises an electric motor; a seal section; a fluid intake; a charge pump assembly located downstream of the fluid intake and having an inlet in fluid communication with an outlet of the fluid intake, having a fluid mover coupled to a drive shaft, and having a fluid reservoir located downstream of the fluid mover; a gas separator assembly located downstream of the charge pump assembly and having an inlet in fluid communication with an outlet of the charge pump assembly; and a production pump assembly located downstream of the gas separator assembly and having an inlet in fluid communication with a liquid phase discharge port of the gas separator assembly.