Human growth hormone(HGH) is a substance produced by a gland in the brain called the pituitary gland. This gland is often called the master gland, because it controls many of the other glands in the body. It is about the size of a pea and it lies above the roof of the mouth, beneath the brain. human growth hormone is a protein and is made of 191 building blocks called amino acids. It is also called somatotropin or somatropin which are the Greek words for body growth.
The pituitary gland secretes human growth hormone throughout a person's life. This growth hormone works by causing other hormones and chemicals, called growth factors, to be produced in the body. These growth factors, along with growth hormone itself, travel through the bloodstream and cause growth and development to occur throughout the body.