Insulin-like Growth Factors (IGFs) are peptide hormones structurally similar to insulin, playing a key role in growth, development, and cellular regulation. There are two main types:

• Primarily produced in the liver in response to growth hormone (GH) stimulation.
• Acts as the main mediator of the anabolic and growth-promoting effects of GH.
• Essential for childhood growth and contributes to tissue repair, muscle maintenance, and metabolic regulation in adulthood.
• Levels decline with age and are influenced by nutrition, exercise, and health status.

• More active during fetal development.
• Functions largely independent of GH.
• Its role in adults remains less clearly understood.

• Mitogenic: Stimulates cell proliferation.
• Anti-apoptotic: Promotes cell survival.
• Binds to IGF receptors, especially IGF-1R, activating pathways such as PI3K-AKT and MAPK.
• Circulates bound to IGF-binding proteins (IGFBPs), especially IGFBP-3, which regulate its bioavailability.

• ↑ IGF-1: Associated with acromegaly, neoplasms, and insulin resistance.
• ↓ IGF-1: Linked to growth disorders, frailty, osteoporosis, and aging.