Carbon capture and utilization (CCU) is a crucial technology for mitigating the effects of climate change. One approach to CCU is reactive carbon capture (RCC), which integrates (1) the capture and concentration of CO₂ in a capture medium via the reversible formation of a chemical complex with a molecular capture agent, such as an amine, and (2) the direct transformation of the CO₂ complex into a fuel or chemical. CO₂ capture media present a large degree of speciation, where carbon exists in different molecular configurations with different energy states and barriers to reaction. In this work, a combination of first principle modeling and experimental electrochemical characterization methods reveal that unbound dissolved CO₂ is the primary carbon species being consumed during the electrochemical reduction of bicarbonate and amine-based CO₂ capture solutions on silver electrodes. Carbon in the CO₂-absorber complex occurs to serve as a second carbon source only at highly negative potential.