What Is IGF-1 LR3?

IGF-1 LR3, also known as long arginine extended insulin-like growth factor 1, is a synthetic analogue of endogenous insulin-like growth factor 1 (IGF-1). This research compound has been investigated in scientific contexts for its structural modifications and signalling properties. Understanding IGF-1 LR3 is critical for researchers working in cell biology and growth factor research.

Structural Differences From IGF-1

IGF-1 LR3 differs from natural IGF-1 through two key modifications: an arginine substitution at position 3 and a 13 amino acid extension at the C-terminus. These structural alterations were engineered specifically to alter binding properties. Research has suggested that these modifications result in reduced binding to insulin-like growth factor-binding proteins (IGFBPs), which theoretically could extend its signalling window in research models. However, all investigations remain in preclinical contexts.

Research Areas

IGF-1 LR3 has been investigated primarily through cellular signalling research via the insulin-like growth factor 1 receptor (IGF-1R). Preclinical studies have examined its interactions within in vitro and animal model systems. The compound serves as a research tool for understanding growth factor receptor activation and downstream signalling cascades. Scientists studying cell proliferation, differentiation, and metabolism have utilized IGF-1 LR3 as an experimental reagent.

For researchers seeking high-quality IGF-1 LR3, TrueCanPeptides supplies IGF-1 LR3 1mg as part of our Research Hub.

Storage Notes

IGF-1 LR3 is supplied in lyophilized form and requires storage at -20°C or lower for optimal stability. This compound is particularly sensitive to freeze-thaw cycles, which can compromise peptide integrity and biological activity. Researchers should minimize the number of freeze-thaw events and follow proper reconstitution protocols.

Purity Standards

Research-grade IGF-1 LR3 must meet rigorous quality and purity standards, typically 98-99% pure. All compounds should be accompanied by comprehensive certificate of analysis documentation confirming identity, purity, and absence of contaminants. Verification of these documents ensures reproducibility and scientific integrity in research.

Research Disclaimer

For research purposes only. Not intended for human use. This content is educational and does not constitute medical advice.

IGF-1 LR3 vs Endogenous IGF-1

Endogenous IGF-1 (insulin-like growth factor 1) is a 70-amino acid peptide produced primarily in the liver in response to growth hormone stimulation. It is a key mediator of GH’s anabolic effects and plays central roles in cell proliferation, differentiation, and survival signalling. Its half-life is approximately 10–20 minutes in circulation, limited by IGF-binding proteins (IGFBPs) that bind and clear it rapidly.

IGF-1 LR3 (Long Arg³ IGF-1) is a synthetic IGF-1 analogue engineered to overcome these limitations. Two modifications distinguish it from native IGF-1:

• N-terminal extension: A 13-amino acid extension added to the N-terminus (the “Long” component) that dramatically reduces IGFBP binding affinity — extending half-life from ~10 minutes to approximately 20–30 hours
• Arg³ substitution: Glutamate at position 3 is replaced by arginine, which also contributes to reduced IGFBP binding

The result is an IGF-1 analogue with equivalent receptor binding activity but dramatically extended pharmacokinetics and reduced IGFBP interference — making it a more tractable research tool for studying IGF-1 receptor (IGF-1R) signalling in cell and animal models.

Structure and Chemistry

• Full name: Long Arginine³ IGF-1; [Arg³] IGF-1 with N-terminal extension
• Amino acids: 83 (70 native IGF-1 + 13 AA N-terminal extension)
• Molecular weight: ~9,117 Da
• Half-life: ~20–30 hours (vs ~10–20 min for native IGF-1)
• Receptor target: IGF-1R (insulin-like growth factor 1 receptor)
• Format: Lyophilized powder
• Solubility: Soluble in 1% acetic acid; transfer to neutral pH buffer for use

IGF-1R Signalling: Research Context

IGF-1R is a tyrosine kinase receptor expressed in virtually all cell types. Activation by IGF-1 or IGF-1 LR3 triggers downstream pathways including:

• PI3K/AKT pathway: Key mediator of cell survival, glucose uptake, and protein synthesis. One of the most frequently studied downstream targets in IGF-1R research.
• MAPK/ERK pathway: Associated with cell proliferation and differentiation signalling. IGF-1 LR3 is used in research models to examine ERK activation kinetics.
• mTOR activation: Via AKT, IGF-1R signalling activates mTOR, which regulates protein synthesis, autophagy, and cell growth — areas of high research interest in both metabolic and cancer biology.

Research Applications

IGF-1 LR3 is used across several research domains:

• Cell culture media supplementation: Used in biopharmaceutical manufacturing to stimulate cell growth in serum-free culture conditions — one of the most established applications
• Muscle biology research: Skeletal muscle cell (myoblast/myotube) models use IGF-1 LR3 to study hypertrophic signalling pathways
• Cancer biology: IGF-1R overexpression is found in many tumour types; LR3 is used as a pharmacological tool to activate IGF-1R in in vitro cancer cell models
• Metabolic research: Insulin/IGF-1 cross-signalling studies use LR3 to dissect receptor-specific contributions to glucose metabolism

Storage and Reconstitution

• Store lyophilized at −20°C; −80°C for long-term storage (>12 months)
• Reconstitute in 1% acetic acid (0.01M) initially; dilute to working concentration in PBS or culture medium at neutral pH
• Do not reconstitute directly in neutral pH buffer — solubility is poor; acetic acid step is required
• Post-reconstitution: aliquot immediately; store at −20°C; avoid repeated freeze-thaw cycles
• Protein-based compound — minimize mechanical stress (no vortexing)

IGF-1 LR3 is supplied by TrueCanPeptides for qualified in vitro laboratory research purposes only. Not for human or animal administration. Not evaluated or approved by Health Canada for therapeutic use.

Available: IGF-1 LR3 1mg from TrueCanPeptides | Growth Peptides catalog | What Are Peptides?