IGF-1 LR3 Research Guide: Long-Arg3 Extended Half-Life Analog
IGF-1 LR3 is a modified 83-amino-acid IGF-1 analog designed to minimize IGFBP binding and extend biological half-life to ~20–30 hours.
What is IGF-1 LR3?
A modified IGF-1 analog originally developed for animal cell culture research (where its low IGFBP binding produces cleaner receptor activation). The extended half-life has since made it a common research peptide in hypertrophy and IGF-1 signaling studies.
Mechanism of action
IGF-1 LR3 binds the IGF-1 receptor with affinity comparable to native IGF-1, activating PI3K/Akt (survival, hypertrophy) and Ras/MAPK (proliferation) cascades. The reduced IGFBP binding minimizes carrier-mediated sequestration and extends functional half-life to 20–30 hours.
Sourcing & purity
Research-grade material should be ≥99% pure by HPLC with peptide content confirmed via mass spectrometry. Redline Bio material ships with batch documentation; independent third-party COAs are published on the lab reports page as testing returns.
Compliance reminder
Sold and distributed for laboratory research use only. Not approved by the FDA for human consumption, diagnosis, treatment, or cure of any disease. Researchers are responsible for compliance with all applicable institutional, state, and federal regulations.
Frequently asked questions
What is IGF-1 LR3?
IGF-1 LR3 (Long Arg³ IGF-1) is a synthetic analog of human IGF-1 with a 13-amino-acid N-terminal extension and an arginine substitution at position 3. The modifications dramatically reduce binding to IGFBP-3 while preserving IGF-1 receptor affinity.
Half-life?
Approximately 20–30 hours in animal pharmacokinetic studies — roughly 100× longer than native IGF-1 (~10 minutes), driven by reduced IGFBP-mediated clearance.
Mechanism?
IGF-1 LR3 binds the IGF-1 receptor and activates PI3K/Akt and Ras/MAPK signaling — the same pathways as endogenous IGF-1, but with substantially longer receptor engagement.