The influence of electrochemistry on the coagulation of blood on metal surfaces was demonstrated several decades ago. In particular, the application of cathodic currents resulted in reduced surface thrombogenicity, but no molecular mechanism has been so far proposed to explain this observation. In this article we used for the first time the quartz crystal microbalance with dissipation monitoring technique coupled with an electrochemical setup (EQCM-D) to study thrombosis at the blood-electrode interface. We confirmed the reduced thrombus deposition at the cathode, and we subsequently studied the effect of cathodic currents on adsorbed fibrinogen (Fg). Using EQCM and mass spectrometry, we found that upon applying currents Fg desorbed from the electrode and was electrochemically degraded. In particular, we show that the flexible N-terminus of the α-chain, containing an important polymerization site, was cleaved from the protein, thus affecting its clottability. Our work proposes a molecular mechanism that at least partially explains how cathodic currents reduce thrombosis at the blood-electrode interface and is a relevant contribution to the rational development of medical devices with reduced thrombus formation on their surface.