IGF-1 LR3 1mg | Muscle Growth & Cell Repair

IGF-1 LR3 is a research-grade long-acting insulin-like growth factor-1 analog studied for muscle protein synthesis, cell proliferation, glucose metabolism and tissue repair. This 3 ml vial containing 1 mg presentation is intended for laboratory investigation of IGF-1 receptor signalling with reduced binding-protein affinity. IGF-1 LR3 is a recombinant analog of insulin-like growth factor-1 with an arginine substitution at position 3 and a 13-amino-acid N-terminal extension. These changes reduce binding to IGF-binding proteins, which extends its half-life and increases free analog availability at the IGF-1 receptor.

Receptor activation triggers the PI3K/Akt pathway, driving protein synthesis and glucose uptake, and the MAPK pathway, driving cell proliferation and differentiation. Tomas and colleagues (Biochemical Journal, 1992) showed that IGF-1 and especially the LR3 variant were anabolic in dexamethasone-treated rats, increasing muscle protein synthesis and growth despite reduced endogenous IGF-1. Subsequent work established that LR3 has a substantially longer clearance time than native IGF-1 in animal models. Laboratories use IGF-1 LR3 to study muscle hypertrophy, satellite-cell activation, chondrocyte and fibroblast proliferation, and the interplay between GH and IGF-1 signalling.

It is also a tool for examining IGF-binding-protein effects on ligand bioavailability. The 1 mg presentation is suited to cell-culture and short rodent protocols, where concentrations are typically in the nanomolar range. Because LR3 binds the insulin receptor with reduced selectivity compared with native IGF-1, studies should include insulin-receptor controls and measure glucose handling alongside growth endpoints. Keep the sealed vial at -20C until use, shield it from light, and reconstitute under sterile conditions with bacteriostatic water or the buffer specified in the study protocol.

Working solutions should be kept cold, aliquoted, and used within the stability window established for that peptide. Key questions concern the relative contribution of IGF-1R versus insulin-receptor activation, the effect of binding-protein milieu on potency, and whether chronic exposure produces desensitisation or receptor downregulation. Supplied exclusively for controlled laboratory research. It is not intended for human consumption, clinical use or therapeutic application.