Human Transferrin Receptor 1 (TfR1/CD71) is a type II transmembrane glycoprotein encoded by the TFRC gene and the primary receptor responsible for cellular uptake of transferrin-bound iron. Through receptor-mediated endocytosis, TfR1 plays a critical role in iron homeostasis, cell growth, and proliferation. Human TfR1 is highly expressed in rapidly dividing cells and has emerged as an important therapeutic target in oncology, immunology, and blood-brain barrier (BBB) drug delivery research. Recombinant human TfR1 is widely used for antibody discovery, binding affinity analysis, epitope mapping, functional characterization, and the development of TfR1-targeting therapeutics and BBB shuttle technologies.