IGF-1 LR3: A Laboratory Research Reference

IGF-1 LR3 is a synthetic analogue of insulin-like growth factor 1 (IGF-1), studied in laboratory research for its interaction with the IGF-1 receptor and related cell-signalling pathways. The "LR3" designation refers to a long-arginine modification at the N-terminus together with a single substitution of glutamic acid for arginine, changes that extend its activity in experimental models.

This page is a non-promotional scientific reference for researchers. It does not provide muscle-growth, anti-ageing, therapeutic, or human-use guidance. IGF-1 LR3 supplied by Bulk Aussie Peptides is for laboratory research purposes only.

Chemical Identity and the LR3 Modification

IGF-1 is a peptide growth factor structurally related to insulin. IGF-1 LR3 is a modified form bearing a long-arginine extension at the N-terminus and an internal glutamic-acid-to-arginine substitution. The principal effect of these changes is to reduce binding to IGF-binding proteins, which in turn extends the free, bioavailable peptide in experimental systems and alters its receptor-interaction profile.

As a synthetic peptide, IGF-1 LR3 is assembled in the laboratory, then purified and characterised before it is supplied for research. For background on production and verification, see the synthetic peptides research guide.

Molecular Characteristics

• Classification: a synthetic analogue of insulin-like growth factor 1 with the LR3 modification.
• Structural modification: long-arginine N-terminal extension and an internal arginine substitution.
• Molecular weight: reported in Daltons (Da) and compared against the theoretical sequence-derived mass.
• Physical form: lyophilised (freeze-dried) powder.

Mechanism as Studied

In laboratory models, IGF-1 LR3 binds to the IGF-1 receptor and engages downstream signalling associated with cell growth and differentiation. Its reduced affinity for IGF-binding proteins distinguishes its signalling behaviour from that of native IGF-1, making it a tool for studying receptor activation in the presence of a longer-lived free ligand. Findings remain preclinical.

Areas of Scientific Research

• IGF-1 receptor pharmacology: activation and downstream growth-signalling pathways.
• Cell growth and differentiation: signalling in cultured cell models.
• Binding-protein influence: the effect of the LR3 modification on bioavailable ligand.

These investigations are conducted in vitro or in approved animal research models under institutional oversight.

Analytical Testing

IGF-1 LR3 is characterised using:

• HPLC for purity assessment.
• Mass spectrometry for identity confirmation by molecular mass.

See how to read a peptide Certificate of Analysis for interpretation guidance.

References and Further Reading

• IGF-1 LR3 and insulin-like growth factor analogues. (Preclinical research literature on IGF-1 receptor signalling and synthetic analogues.)
• HPLC Peptide Testing Explained.
• Reading a Peptide Certificate of Analysis.