IGF-1 LR3: Long-Acting Insulin-like Growth Factor Research Guide

<p>IGF-1 LR3 (Insulin-like Growth Factor-1 Long Arg3) is a synthetic analog of IGF-1 with an 83-amino acid sequence incorporating an N-terminal 13-amino acid extension and a glutamic acid to arginine substitution at position 3. These modifications substantially reduce IGF-1 LR3's affinity for IGF binding proteins (IGFBPs), resulting in a dramatically extended half-life relative to native IGF-1 — approximately 20-30 hours vs. minutes for the unmodified peptide.</p><h2>Molecular Profile</h2><p>MW: 9117.6 g/mol | CAS: 946870-92-4 | Modification: N-terminal Met-Arg extension + Glu3→Arg3 substitution | Half-life advantage: ~20-30h vs. native IGF-1</p><h2>IGF-1 Receptor Signaling</h2><p>IGF-1 LR3 binds the type 1 IGF receptor (IGF-1R), a receptor tyrosine kinase that activates PI3K/Akt and MAPK/ERK signaling cascades — pathways central to cell proliferation, survival, protein synthesis, and glucose metabolism. Because IGF-1 LR3 has minimal IGFBP binding, the free active fraction available for receptor engagement is significantly higher and more sustained than native IGF-1 at equivalent concentrations.</p><h2>Research Applications</h2><ul><li>Cell proliferation and anabolic pathway studies in culture</li><li>PI3K/Akt signaling cascade research</li><li>Satellite cell (muscle stem cell) biology research</li><li>Glucose uptake and GLUT4 translocation pathway studies</li><li>Comparison studies with native IGF-1 for binding kinetics</li><li>Cancer biology research — IGF-1R overexpression models</li></ul><h2>Frequently Asked Questions</h2><p>Q: Why does IGF-1 LR3 have a longer half-life than native IGF-1?</p><p>A: The N-terminal modification and Arg3 substitution dramatically reduce IGFBP binding affinity, preventing the protein-binding that normally sequesters and inactivates IGF-1 rapidly in biological systems.</p><p>Q: What is the difference between IGF-1 and IGF-1 LR3 for research use?</p><p>A: IGF-1 LR3 provides a more sustained receptor activation profile due to reduced IGFBP binding. Native IGF-1 is rapidly sequestered by IGFBPs, limiting its free active fraction. The choice depends on whether your model requires acute or sustained IGF-1R stimulation.</p><p>Related: IGF-1 LR3 Product → | CJC-1295 Research Guide → | Ipamorelin Research Guide → | Tesamorelin Research Guide →</p>