During the electrocatalytic hydrogen evolution reaction (HER), the second Wien effect enhances the dissociation of weak electrolytes when exposed to high electric fields. This enhanced dissociation impacts the reactant-switching mechanism, promoting the production of free protons that facilitate HER. In this study, we examine the extent of field-induced dissociation utilizing the generalized modified Poisson-Nernst-Plank (GMPNP) model, which incorporates electric-field-enhanced ion dissociation to simulate ion distributions and resulting proton limiting current densities in both unbuffered and buffered electrolytes. Specifically, we compare unbuffered conditions using KClO 4 with buffered systems using K-carbonate and K-phosphate. The findings reveal that strong field sensitivity may lead to an overestimation of water dissociation, especially in unbuffered conditions. Notably, in the presence of buffer species, field-enhanced protolysis allows free protons to serve as effective HER reactants at current densities exceeding several hundred mA cm −2. In the diffuse layer, the effective proton concentration surpasses that in the bulk due to the electric-field-driven dissociation of buffer species. This study emphasizes the critical role of interfacial electric fields in modulating local ion availability and highlights computational modeling as a powerful tool for visualizing nearelectrode ion distributions�an aspect challenging to capture experimentally.