Insulin-like growth factors are a group of peptides with growth-promoting effects. Secretory cells are widely distributed among human tissues such as liver, kidney, heart, lung, brain and intestine. Growth insulin-like growth factors include type I and type II, with type I production being more dependent on growth hormone and its growth-promoting effect being enhanced, making it an important growth factor during childhood. Insulin-like growth factor I, which is synthesized in various tissues, mostly exerts its growth-promoting effects in an endocrine or paracrine form. In contrast, insulin-like growth factor I synthesized by the liver enters the blood circulation and acts on target cells in an endocrine manner. The level of insulin-like growth factor I in the body is regulated by growth hormone and also has a negative feedback regulation on the secretion of growth hormone. Insulin-like growth factor II has an important role in cell proliferation and differentiation, growth and development, and maintenance of energy metabolism.