Mouse serum albumin (MSA) is a ubiquitous protein of the blood plasma in mice, constituting approximately half of the total protein content. Due to its exceptional ligand-binding capacity, MSA serves as multifunctional carrier protein, transporting various endogenous and exogenous ligands, including fatty acids, bilirubin, hormones, metal ions, and drugs. Its ability to bind these ligands with high affinity and specificity facilitates their distribution, metabolism, and elimination within the body. Additionally, MSA acts as scavenger of reactive oxygen species (ROS), thereby preventing oxidative damage to cells and tissues. Furthermore, MSA essentially contributes to the regulation of oncotic pressure to ensure fluid balance between the intravascular and interstitial compartments and to prevent edema. Alterations in MSA levels or function are associated with a range of clinical conditions, such as liver disease, kidney dysfunction, malnutrition, and inflammation. In biomedical research, MSA serves as a valuable tool, used as a standard reference for various assays and experiments, including protein binding studies, drug delivery systems, and diagnostic assays.