IGF-1 LR3

IGF-1 LR3 (Long R3 Insulin-Like Growth Factor-1) is a synthetic, modified form of human IGF-1. The modification replaces glutamic acid at position 3 with arginine and adds 13 amino acids to the N-terminus. These changes dramatically reduce binding to IGF-binding proteins (IGFBPs), resulting in a more potent and longer-acting version with a half-life of approximately 20-30 hours compared to 12-15 minutes for native IGF-1.

The reduced IGFBP binding means IGF-1 LR3 remains largely free and biologically active in circulation, making it approximately 2-3 times more potent than native IGF-1 in stimulating cell growth. IGF-1 is a central mediator of growth hormone's anabolic effects and plays crucial roles in muscle protein synthesis, cell proliferation, and cell survival across virtually all tissue types.

IGF-1 LR3 has been extensively used in cell culture research as a growth factor and studied in animal models for anabolic applications. Its potent properties have made it popular in performance communities. However, this potency also raises significant safety concerns, as IGF-1 signaling is a known growth factor for many cancer types, and elevated IGF-1 levels have been epidemiologically associated with increased cancer risk.

The use of a modified IGF-1 with enhanced potency carries risks of promoting growth of undiagnosed neoplasms. Additionally, IGF-1 affects glucose metabolism, and inappropriate use can lead to hypoglycemia. These risks underscore the need for caution and medical supervision.