Interleukin-6 (IL-6) is a pleiotropic cytokine with critical roles in both innate and adaptive immunity. It functions as a proinflammatory mediator and an anti-inflammatory myokine, reflecting its diverse physiological effects. IL-6 is secreted by immune cells, fibroblasts, endothelial cells, and adipocytes in response to infection, tissue injury, or metabolic stress. It signals through IL-6R in complex with the gp130 co-receptor, activating JAK/STAT3, MAPK, and PI3K pathways. IL-6 regulates numerous biological processes, including acute-phase protein synthesis in hepatocytes, B-cell differentiation and antibody production, T-cell polarization, and the modulation of metabolic and neural circuits. Aberrant IL-6 signaling contributes to chronic inflammation, autoimmune disease, cardiovascular disorders, metabolic dysfunction, cancer, and neuroinflammatory conditions. Catalina offers rigorously validated IL-6 antibodies that deliver high sensitivity and specificity, ensuring accurate IL-6 detection and characterization of this cytokine.