The invention "colloidal nanoscale carriers for active hydrophilic substances and method for producing same" pertains to the field of medical, odontological or hygiene preparations, and is characterised by structures formed by hydrophilic polymers that contain active hydrophilic substances coated with a non-hydrophilic phase and surfactants with affinity for the components, forming an invert emulsion that allows the incorporation and controlled delivery of active hydrophilic substances, conferring properties such as protection against degradation processes, improvement of compatibility with the other components of the formulation in the final product, increase in the availability and/or bioavailability of the active substance in the medium of interest (including improvements in permeation processes in biological materials, reduction of the exposure and volatilisation of the active substance in the medium) and controlled release of the active substance(s). The nanoscale carrier obtained by this method, called colloidal nanoscale carrier (NC), can be used in various fields, such as the pharmaceutical field (including dermatology), cosmetics, personal hygiene products, veterinary medicine, agrochemicals and fertilizers, the food industry and the like. The invention proposes a kinetically stable system with an effective nanoscale structure that consists of nanoscale carriers formed by polymers emulsified in a non-aqueous medium in the presence of a surfactant with affinity for the two phases (the dispersion medium and the encapsulating agent). This system is obtained by nanoemulsification of an aqueous phase of hydrophilic polymers emulsified in a non-hydrophilic (lipophilic or silophilic) phase that contains the surfactants, and is characterised by the implementation of two concepts that encompass the generation of an invert nanoscale emulsion and of polymer nanoparticles. The formulation has the novel technical effect of providing a polymer excipient with a nanoscale structure for delivering hydrophilic molecules suspended in a non-hydrophilic phase, which allows controlling the size of the nanoscale particles and modulating colloidal stability by means of process parameters.