2020-12-21 20:10 Human chorionic gonadotropin (HCG), a polypeptide hormone produced by the human placenta. HCG is composed of an alpha and a beta sub-unit. The alpha sub-unit is essentially identical to the alpha sub units of the human pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), as well as to the alpha sub-unit of human thyroid-stimulating hormone (TSH), while the beta sub units of these hormones differ in amino acid sequence.