IGF-1 (LR3)

IGF-1 LR3

IGF-1 LR3 (Long R3 IGF-1) is an engineered 83-amino-acid analog of human insulin-like growth factor-1. Compared with the native 70-residue protein, it carries a 13-amino-acid extension at the N-terminus and an arginine in place of glutamic acid at position 3 (the “R3”). Both changes were made to reduce binding to IGF-binding proteins, and the analog was developed in Australia in the late 1980s and early 1990s, originally with cell-culture applications in mind.

Product Specifications

• Product: IGF-1 LR3
• Amount: See available options above
• Form: Lyophilized powder
• Purity: Third-party tested by an ISO 17025 U.S. laboratory. See the batch Certificate of Analysis (COA) on this page.
• Storage: Keep sealed and refrigerated at 2–8°C (36–46°F), protected from light.
• Ships from: United States, 2-day UPS

Chemical Profile

• Compound class: Synthetic IGF-1 analog, 83 amino acids (formula and weight calculated from sequence)
• Molecular formula: C₄₀₀H₆₁₉N₁₁₁O₁₁₅S₉
• Molecular weight: 9111.6 g/mol
• CAS number: 143045-27-6

What researchers study

IGF-1 acts through the IGF-1 receptor, a receptor tyrosine kinase coupled to PI3K/Akt and MAPK/ERK signaling. In tissue fluids and culture media, six IGF-binding proteins capture most free IGF-1, limiting how much reaches the receptor. Long R3 IGF-1 binds those proteins very weakly while keeping receptor activity, so it is used where researchers want a steady IGF-1 receptor signal that is not buffered by binding proteins.

• Cell culture and bioprocessing: Long R3 IGF-1 is widely used as a defined growth-factor supplement in serum-free media for mammalian cell lines, including production cell lines.
• Receptor signaling: IGF-1 receptor activation, downstream kinase signaling and cross-talk with the insulin receptor in cultured cells.
• IGFBP function: side-by-side comparison with native IGF-1 and with des(1-3)IGF-1 to separate binding-protein effects from receptor effects.
• Preclinical tissue models: rodent studies of the gut, muscle and other tissues under IGF-1 receptor stimulation.

Regulatory status

IGF-1 LR3 is not approved by the FDA for any use. IGF-1 and its analogs are covered by the World Anti-Doping Agency’s Prohibited List under S2. It is sold here as a research reagent only.

Quality & Documentation

Every batch of IGF-1 LR3 is made in small runs for Rogue Compounds and tested by an independent U.S. laboratory for identity (mass spectrometry) and purity (HPLC). Each vial is labeled with its batch number and a QR code that opens the testing lab’s own report for that batch. The same batch Certificate of Analysis is posted on this page and in our COA Library, so you can check one against the other.

Research overview

For a longer look at IGF-1 LR3, covering where it came from, what cell and animal studies have measured, and what the evidence does not show, read our IGF-1 LR3 research overview. It is written as background reading, and every study it cites is linked to PubMed.

Selected literature

• Francis GL, et al. Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency. J Mol Endocrinol. 1992;8(3):213-23. PMID 1378742
• Tomas FM, et al. IGF-I variants which bind poorly to IGF-binding proteins show more potent and prolonged hypoglycaemic action than native IGF-I in pigs and marmoset monkeys. J Endocrinol. 1997;155(2):377-86. PMID 9415072
• Conlon MA, et al. Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig. J Endocrinol. 1995;146(2):247-53. PMID 7561636
• Tomas FM, et al. Insulin-like growth factor-I and more potent variants restore growth of diabetic rats without inducing all characteristic insulin effects. Biochem J. 1993;291 ( Pt 3)(Pt 3):781-6. PMID 7683875
• Lord AP, et al. Differences in the association of insulin-like growth factor-I (IGF-I) and IGF-I variants with rat, sheep, pig, human and chicken plasma-binding proteins. J Endocrinol. 1994;140(3):475-82. PMID 7514204
• Mongongu C, et al. Detection of LongR(3) -IGF-I, Des(1-3)-IGF-I, and R(3) -IGF-I using immunopurification and high resolution mass spectrometry for antidoping purposes. Drug Test Anal. 2021;13(7):1256-1269. PMID 33587816

Research Use Only

This product is sold strictly as a research chemical for in-vitro laboratory and analytical use by qualified professionals. It is not a drug, dietary supplement, food, or cosmetic, and it is not intended to diagnose, treat, cure, or prevent any disease. Not for human or veterinary use. Rogue Compounds does not provide dosing, preparation, or usage instructions. The literature on this page is listed for scientific background only and does not describe this product or any use of it.