Human serum albumin (HSA) is a ubiquitous protein of the human blood plasma, constituting approximately half of the total protein content. Due to its exceptional ligand-binding capacity, HSA 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, HSA acts as scavenger of reactive oxygen species (ROS), thereby preventing oxidative damage to cells and tissues. Furthermore, HSA essentially contributes to the regulation of oncotic pressure to ensure fluid balance between the intravascular and interstitial compartments and to prevent edema. Its unique properties prove HSA useful in several clinical applications. HSA is commonly used as a plasma expander to restore blood volume in patients with hypovolemia or shock. In addition, HSA-based solutions are employed in the formulation of pharmaceutical drugs to enhance their solubility, stability, and pharmacokinetic profiles. Moreover, HSA represents a valuable diagnostic marker used to assess liver function, nutritional status, and inflammatory conditions.