Selenium is an essential element that plays an important role in many biological functions. Many studies have reported the potential beneficial effects of Se intake for cancer therapy and prevention, which are not only dose-dependent but also closely related to the properties of specific selenospecies. Selenium nanoparticles are considered a novel selenium compound with excellent antioxidant properties; however, little is known about the properties of selenium nanoparticles in comparison to other well-studied selenospecies. Here, we combined different independent bioanalytical approaches to carry out a comparison between the effects of selenium nanoparticles and other selenocompounds (inorganic and organic selenospecies) using an in-vitro model. The bioanalytical characterization of different parameters such as cell proliferation, apoptosis and cell cycle pattern on HepG2 cells has shown the unique properties of this relatively novel compound that support and complete prior evidences for future applications as chemotherapeutic agent.