IGF-1 LR3 is a synthetic analog of insulin-like growth factor-1 (IGF-1). It is a modified version of the naturally occurring IGF-1, a peptide hormone that plays a crucial role in growth and development. Operating at a cellular level, it is used to stimulate muscle growth and is believed to enhance protein synthesis and contribute to the development of lean muscle mass. It has has insulin-like effects on glucose metabolism and can increase glucose uptake by cells, promoting energy utilization. The “LR3” in its name refers to the substitution of Arginine for Glutamic Acid at position 3, which extends the half-life of the peptide, making it more stable in the body.