What is IGF-1 LR3?

IGF-1 LR3 is a synthetic analog of insulin-like growth factor 1 (IGF-1) engineered for an extended half-life and enhanced biological stability. The “LR3” designation refers to a long arginine 3 modification—an amino acid substitution that reduces binding to IGF-binding proteins (IGFBPs), allowing more IGF-1 to interact with its receptors in experimental systems.

IGF-1 is a naturally occurring peptide hormone involved in cell growth, differentiation, and repair. This LR3 version is supplied as a 1mg lyophilized vial for research purposes only.

Mechanism of Action

IGF-1 LR3 binds to the IGF-1 receptor (IGF1R) and activates intracellular signaling cascades such as the PI3K/Akt and MAPK/ERK pathways. These pathways regulate cell survival, protein synthesis, and tissue regeneration.

By reducing binding to IGFBPs, IGF-1 LR3 maintains higher free concentrations in circulation, extending its activity window compared to native IGF-1 in research models.

Research Applications

• Cell growth, proliferation, and differentiation studies
• Muscle regeneration and repair models
• Nerve regeneration and neuroprotection research
• Bone density and connective tissue studies
• Comparative analysis vs. native IGF-1

In vitro and in vivo models often measure protein synthesis rates, tissue repair markers, and anabolic gene expression in response to IGF-1 LR3 exposure.

Chemical Profile

Sequence: Modified human IGF-1 with arginine substitution at position 3 and an extended N-terminal peptide
Molecular Formula: C400H625N111O115S5
Molecular Weight: ~9111 g/mol

The LR3 modification increases biological half-life from minutes to hours in research systems, making it more suitable for extended observation windows.

Comparison to Native IGF-1

Native IGF-1 is rapidly bound by IGFBPs, limiting free circulation time. IGF-1 LR3’s reduced binding affinity allows for prolonged receptor activation, making it advantageous for long-term signaling studies.

Storage & Stability

Store lyophilized IGF-1 LR3 at −20°C, protected from light and moisture. After reconstitution, refrigerate at 2–8°C and use within protocol-specific timelines. Avoid repeated freeze–thaw cycles.

For Research Use Only

IGF-1 LR3 1mg is intended strictly for laboratory research by qualified personnel. Not for human or veterinary use. All handling must comply with applicable regulations.

• IGF-1 – Wikipedia
• IGF-1 Receptor – Wikipedia
• IGF Binding Proteins – Wikipedia
• PI3K/Akt Pathway – Wikipedia