The investigation of electrocatalytic nanoeffects is tackled via joint electrochemical measurements and computational simulations. The cyclic voltammetry of electrodes modified with metal nanoparticles is modeled considering the kinetics of the electrochemical process on the bulk materials of the different regions of the electrode, that is, the substrate (glassy carbon) and the nanoparticles (gold). Comparison of experimental and theoretical results enables the detection of changes in the electrode kinetics at the nanoscale due to structural and/or electronic effects. This approach is applied to the experimental assessment of electrocatalytic effects by gold nanoparticles (Au NPs) in the electrooxidation of nitrite and L-ascorbate. Glassy carbon electrode is modified with Au NPs via seed-mediated growth method. Divergence between the kinetics of these processes on gold macroelectrodes and gold nanoparticles is examined. Whereas claimed catalytic effects are not observed in the electrooxidation of nitrite, electrocatalytic nanoeffects are verified in the case of L-ascorbate. This is probably due to that the electron transfer process follows an adsorptive mechanism. The combination of simulation with experiments is commended as a general strategy of authentification, or not, of nanoelectrocatalytic effects.