A manually energized dispensing system containing a dispensing head (1) which has a housing (2), a nozzle, a pump (4) mounted in the housing, and a pump actuation mechanism (3) is provided. The pump has a pump rotor (13) and a stator (12). The pump rotor has two axial extensions (17, 18) of different diameters, mounted in corresponding chambers (15, 16) of the stator, and first and second seals (19, 20) mounted in the stator housing and surrounding the first and second axial rotor extensions. The rotor extensions comprising liquid supply channels (22, 24), in conjunction with the seals operate as valves that open and close communication between an inlet of the pump connected to the inside of a container (7) and the pump chambers, respectively. The pump chambers are operated as a function of the angular displacement of the pump rotor.