Use DSC to follow the stability of antibodies during the critical steps of manufacturing. There are multiple challenges to overcome while developing formulations for proteins intended as therapeutics. Most notably, project timelines and often limited initial availability of material drive the need for rapid, robust, and sensitive formulation development tools. Thermodynamic analysis has proven to be an invaluable approach to aid in the characterization of physical protein instabilities. However, the generated thermodynamic parameters, such as melting temperature (Tm), are typically apparent rather than absolute. Even with this caveat, apparent thermodynamic parameters are indispensable in rapidly evaluating protein instabilities. Differential Scanning Calorimetry (DSC) is a key tool in the analytical arsenal of a formulation development scientist. DSC allows for the determination of calorimetric melting temperatures and enthalpies of unfolding that permit an assessment of protein solution behavior under a variety of conditions. Several examples of pre-formulation and later-stage formulation applications of DSC, as well as their limitations and other special considerations, are discussed. These examples illustrate the crucial role of DSC and thermodynamic analysis during therapeutic protein development.