Human chorionic gonadotropin, also known as hCG, is a naturally-occurring hormone which is produced by the placenta . The hCG hormone is composed of two units, which are known as the alpha and beta subunits  Moreover, hCG refers to four independent molecules in which each shows different function, and each being produced by separate cells .
How it works
hCG is known to have luteinizing hormone-like activity . Luteinizing hormone function in females is based on the initiation of ovulation; in males, this hormone triggers Leydig cells to produce testosterone. In addition, hCG has a half-life, or lasts for, around 37 hours .