Insulin (human) is a recombinant peptide hormone composed of 51 amino acids, primarily utilized as a biochemical reagent in laboratory research. It is essential for studies on diabetes mellitus, glucose metabolism, insulin signaling pathways, and cell signaling mechanisms. In experimental settings, it facilitates the uptake of glucose into cells by activating GLUT4 transporters, thereby regulating cellular energy homeostasis. This reagent is commonly employed in cell culture media to support the growth and maintenance of insulin-dependent cell lines, such as pancreatic beta cells or adipocytes. It is also used in in vitro assays for investigating insulin resistance, hormone-receptor interactions, and metabolic disorders. Supplied as a white to off-white solid, it is soluble in dilute hydrochloric acid solutions. For research use only; not intended for therapeutic applications in humans.