Insulin-like growth factor-1 (IGF-1) is a 70-amino-acid polypeptide structurally homologous to insulin. It is produced primarily by the liver in response to growth hormone signaling and acts as the major mediator of GH's anabolic effects.

The most common research analog is IGF-1 LR3, in which an N-terminal 13-amino-acid extension and an Arg³ substitution reduce binding to IGF-binding proteins, prolonging its biological half-life.

IGF-1 has been studied extensively in research on cellular growth, differentiation, anabolism, glucose metabolism, and neuroprotection.

For research purposes only. Not for human consumption.