Overview
IGF-1 LR3 is an 83-amino-acid analogue of human insulin-like growth factor 1. It differs from the native 70-residue hormone in two ways: glutamic acid at position 3 is replaced with arginine, and a 13-amino-acid extension is added to the N-terminus. Together these changes greatly reduce binding to IGF-binding proteins, the carriers that normally sequester most circulating IGF-1.
Because more of the analogue remains free to engage the IGF-1 receptor, IGF-1 LR3 is considerably more potent than native IGF-1 in many in-vitro systems. This property has made it a standard supplement in serum-free in vitro research method.">cell culture media, including industrial bioprocessing. Whole-organism data are sparse, and there are no clinical trials supporting human use. It is not an approved medicine and is prohibited in sport. We supply IGF-1 LR3 for cell-culture and receptor-signalling research.
Mechanism studied
- IGF-1 LR3
- Reduced IGFBP binding
- IGF-1 receptor
- PI3K–Akt / MAPK
IGF-1 LR3 activates the IGF-1 receptor, a receptor tyrosine kinase. Ligand binding triggers autophosphorylation and recruitment of insulin receptor substrate proteins, leading to activation of the PI3K–Akt pathway, which promotes protein synthesis and cell survival, and the Ras–MAPK pathway, which drives proliferation. Its reduced affinity for IGF-binding proteins means a larger fraction of the analogue stays bioavailable in culture media or tissue, prolonging receptor activation compared with native IGF-1. Insulin-receptor cross-activation is weak at typical research concentrations.
Research highlights
- 0183-residue analogue with Arg3 substitution and a 13-residue N-terminal extension
- 02Markedly reduced binding to IGF-binding proteins increases free, active ligand
- 03Widely used as a growth supplement in serum-free and bioprocess cell culture
- 04No clinical trials support use in humans
- 05Prohibited in sport under WADA class S2
Research areas
- Cell culture media supplementation
- IGF-1 receptor signalling
- IGFBP interaction studies
- Myoblast growth models
Evidence & regulatory status
Overall status: Not approved — research
Key references
- [1]PubMed — reviews on IGF-1 LR3
- [2]WADA — Prohibited List of Substances and Methods
Latest published research
65 papers on PubMed →The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration
Dominikowski A et al. · Frontiers in endocrinology · 2026 · PMID 42395176
Revolutionary decellularized Alstroemeria stem-based nerve conduit integrated with GelMA and controlled IGF-1 LR3 release for enhanced rat sciatic nerve regeneration
Yavuz E et al. · International journal of biological macromolecules · 2025 Nov · PMID 41015370
IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep
White A et al. · American journal of physiology. Endocrinology and metabolism · 2025 Jan 1 · PMID 39679943
Intranasal long R3 insulin-like growth factor-1 treatment promotes amyloid plaque remodeling in cerebral cortex but fails to preserve cognitive function in male 5XFAD mice
Engel MG et al. · Journal of Alzheimer's disease : JAD · 2025 Jan · PMID 39610283
Recombinant expression of IGF-1 and LR3 IGF-1 fused with xylanase in Pichia pastoris
Lu Z et al. · Applied microbiology and biotechnology · 2023 Jul · PMID 37261455
Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets
White A et al. · Journal of developmental origins of health and disease · 2023 Jun · PMID 37114757
N-Linked Glycosylation in Chinese Hamster Ovary Cells Is Critical for Insulin-like Growth Factor 1 Signaling
Salvi R et al. · International journal of molecular sciences · 2022 Nov 29 · PMID 36499281
Sheep recombinant IGF-1 promotes organ-specific growth in fetal sheep
Stremming J et al. · Frontiers in physiology · 2022 · PMID 36091374
Live feed from PubMed (NCBI) for “IGF-1 LR3”, updated 2026-10-30. Listing a paper is not an endorsement of its findings.
FAQ
Many laboratories dissolve IGF-1 LR3 in a dilute acidic solution, such as 10 mM hydrochloric acid or 0.1% acetic acid, to aid solubility before further dilution in culture medium. Always confirm compatibility with your assay and follow the guidance on the certificate of analysis.
Lyophilized IGF-1 LR3 is normally kept sealed at −20 °C, protected from light and moisture. Once reconstituted for laboratory work, aliquots are held at 2–8 °C for short-term use or frozen, avoiding repeated freeze–thaw. Follow the lot-specific guidance on the certificate of analysis.
Every lot of IGF-1 LR3 ships with a certificate of analysis reporting HPLC purity, mass-spectrometry identity against the expected molecular weight, appearance and lot number. Match the COA lot to the vial label and keep it with your experimental records.
Last updated October 2026 · Reviewed by the Purity Peptides research team · Information is a summary of published literature and is not a recommendation for any use.
