An instrument (23) for filling a substance supply container (1) of a device (21) for personal care treatment has a filling needle (4) having a proximal end connected or connectable to a storage reservoir (22) and a distal end, a substance transport conduit (9) extending from the proximal end to at least one outlet (10, 11) provided in a radially facing surface portion closely adjacent the distal end of the filling needle (4). A sleeve (14, 15) is arranged around the filling needle (4) and is movable between a first position closing off the at least one outlet (10, 11) and a second position proximally away from the first position and the at least one outlet (10, 11). A system (20) including such an instrument (23), a container (1) for cooperation with such an instrument (23) and for provisioning a device (21) for personal care treatment as well as a device (21) for personal care treatment including such a container (1) are described.