IGF-1 LR3 (Receptor Grade) is a highly purified, research-focused form of the synthetic peptide IGF-1 LR3, designed for experimental use in cellular and receptor-level studies. Like standard IGF-1 LR3, it is a long-acting analogue of insulin-like growth factor 1 (IGF-1), a naturally occurring peptide hormone critical for growth, tissue repair, and metabolic regulation.
This “receptor-grade” version is intended for research applications that require high potency and purity to study IGF-1 receptor interactions specifically. It is not approved as a pharmaceutical or therapeutic product.
What Is IGF-1 LR3
IGF-1 LR3 is a modified form of endogenous IGF-1, created to extend its half-life and reduce binding to IGF-binding proteins. These modifications allow it to act more efficiently at IGF-1 receptors on target cells, promoting cellular growth and repair.
The receptor-grade form emphasizes high purity and bioactivity, making it suitable for precise in vitro or preclinical studies of IGF-1 signaling pathways.
How IGF-1 LR3 (Receptor Grade) Works
IGF-1 LR3 binds directly to IGF-1 receptors on the surface of cells. Once activated, these receptors trigger intracellular signaling cascades that promote:
Protein synthesis
Cell proliferation
Tissue repair and regeneration
Nutrient uptake
Metabolic regulation
Because it bypasses upstream growth hormone signaling, IGF-1 LR3 provides a more direct and potent activation of these pathways compared with growth hormone–stimulating peptides.
Potential Areas of Research Interest
IGF-1 LR3 (Receptor Grade) is primarily studied in experimental and laboratory settings, including research into:
Muscle cell growth and regeneration
Satellite cell activation and proliferation
Recovery from tissue injury
Bone, cartilage, and connective tissue repair
Cellular metabolism and nutrient signaling
IGF-1 receptor mechanisms and binding dynamics
Its receptor-grade formulation allows researchers to examine precise interactions without interference from impurities or variable activity.
Biochemical Characteristics

Sequence: MFPAMPLSSLFVNGPRTLCGAELVDALQFVCGDRGFYFNKPTGYGSSSRRAPQTGIVDECCFRSCDLRRLEMYCAPLKPAKSA
Molar Mass: 9,111 Da
Synonyms: Long Arg3 IGF-1 (Receptor Grade), Long R3 IGF-1
IGF-1 LR3 differs from native IGF-1 through amino-acid substitution and N-terminal extension, which collectively reduce IGFBP interaction while preserving high-affinity binding to IGF-1R. These properties make IGF-1 LR3 a useful probe for isolating receptor-specific signaling events without confounding sequestration by endogenous binding proteins in experimental matrices.
Research Applications
- IGF-1 receptor binding and activation assays
- Signal transduction studies involving PI3K/AKT and MAPK/ERK pathways
- Comparative analyses of IGFBP-dependent versus IGFBP-resistant IGF analogs
- Cell proliferation, differentiation, and apoptosis modeling in cultured cell systems
- Receptor kinetics and downstream phosphorylation mapping
- Preclinical in-vivo (animal) studies examining IGF-axis biology
Receptor Grade IGF-1 LR3 is commonly selected for experiments requiring robust and sustained IGF-1R engagement under tightly controlled laboratory conditions.
Pathway / Mechanistic Context
IGF-1 LR3 primarily interacts with the insulin-like growth factor-1 receptor (IGF-1R), a transmembrane tyrosine kinase receptor. Ligand binding induces receptor autophosphorylation, initiating downstream signaling cascades including:
- PI3K → AKT signaling associated with cellular survival and metabolic regulation
- RAS → RAF → MEK → ERK signaling involved in cell cycle progression and differentiation
Due to its reduced affinity for IGFBPs, IGF-1 LR3 demonstrates prolonged receptor availability in experimental systems, enabling extended interrogation of receptor-proximal and downstream signaling events. Limited cross-interaction with the insulin receptor has also been reported in biochemical assays, providing additional context for comparative receptor specificity studies.
Preclinical Research Summary
Preclinical investigations utilizing IGF-1 LR3 focus on elucidating IGF-axis biology rather than organism-level outcomes. In cell-based and animal models, IGF-1 LR3 has been employed to:
- Characterize receptor binding affinity and internalization dynamics
- Quantify downstream phosphorylation profiles of IGF-1R substrates
- Model regulatory mechanisms governing cell survival and programmed cell death
- Examine differentiation pathways in lineage-specific progenitor cells
All findings reported in the literature are derived from controlled in-vitro or animal-based experimental systems and are interpreted strictly within a mechanistic research framework.
Form & Analytical Testing
This product is supplied as a lyophilized peptide for laboratory research use. Analytical characterization typically includes identity confirmation and purity assessment using orthogonal methods such as high-performance liquid chromatography (HPLC) and mass spectrometry (MS).
Researchers should employ standard peptide handling practices, including controlled reconstitution, appropriate buffer selection, and minimization of adsorption or degradation, to ensure experimental consistency.




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