Human chorionic gonadotropin (hCG) is a hormone produced by the embryo after implantation. The presence of hCG is detected in some pregnancy tests (HCG pregnancy strip tests). Some cancerous tumors produce this hormone; therefore, elevated levels measured when the patient is not pregnant can lead to a cancer diagnosis and, if high enough, paraneoplastic syndromes. However, it is not known whether this production is a contributing cause or an effect of carcinogenesis. The pituitary analog of hCG, known as luteinizing hormone (LH), is produced in the pituitary gland of males and females of all ages.
Regarding endogenous forms of hCG, there are various ways to categorize and measure them, including total hCG, C-terminal peptide total hCG, intact hCG, free β-subunit hCG, β-core fragment hCG, hyperglycosylated hCG, nicked hCG, alpha hCG, and pituitary hCG. Regarding pharmaceutical preparations of hCG from animal or synthetic sources, there are many gonadotropin preparations, some of which are medically justified and others of which are of a quack nature. As of December 6, 2011, the United States FDA has prohibited the sale of “homeopathic” and over-the-counter hCG diet products and declared them fraudulent and illegal.