Development of innovative nutraceuticals for oral administration by using green and sustainable formulation approaches that fit into the principles of the circular economy is particularly dynamic and contemporary area of research.This research investigated the possibilities of green synthesis of Se nanoparticles using excipients that can be isolated from food waste by applying simple and green procedures. Functional characterization of the obtained nanosystems was carried out with special emphasis put on the investigation of on gastrointestinal stability. In the synthesis process pectins of different degrees of purity (raw and purified) and from different sources (tangerine peel and tomato pomace) were used as stabilizing agents, and for the purpose of additional functionalization of the surface of the resulting nanosystems, olive pomace extract rich in polyphenols was used. The properties of nanoparticles before and after in vitro digestion simulation were characterized by determining the particle size distribution, zeta potential, polydispersity index and total reduction potential.The proposed green synthesis procedure resulted in the creation of stable selenium nanosystems with appropriate physicochemical properties. Olive waste derived polyphenols were successfully applied to functionalize the surface of selenium nanoparticles and significantly increase the reduction potential of obtained nanoparticles. Even though digestion process altered particular physicochemical characteristics of the investigated nanosystems, all investigated nanoparticles remained stable and applicable for per os application.Obtained results will contribute to current knowledge about the possibilities of sustainable formulations of innovative per os selenium formulations with improved biopharmaceutical properties.