Insulin-like Growth Factor-1 (IGF-1) is a hormone consisting of 70 amino acids showing a similar molecular structure to insulin and plays a crucial role in growth and development. It is mainly produced by the liver, but also by other tissues, including muscles, bones, and cartilage.

The primary function of IGF-1 is to promote cell growth and division, particularly in bone, muscle, and cartilage tissues. IGF-1 plays roles by binding to the IGF-1 receptor (IGF-1R) on the surface of cells, which triggers a cascade of signaling events that activate various intracellular pathways, such as the PI3K/AKT and MAPK/ERK pathways. These pathways regulate cellular processes such as protein synthesis, cell proliferation, and differentiation.
IGF-1 is regulated by growth hormone (GH), which is produced by the pituitary gland. GH stimulates the liver to produce IGF-1, which is released into the bloodstream and circulates to target tissues.