Description

IGF-1 LR3 (Long Arg³ Insulin-like Growth Factor-1) is an 83-amino acid recombinant analog of insulin-like growth factor 1, modified with an arginine substitution at position 3 and a 13-residue N-terminal extension. This listing is for research-grade IGF-1 LR3 peptide supplied as a 1mg lyophilized powder at ≥98% purity by HPLC. For laboratory research use only. Not for human consumption, veterinary use, food, or therapeutic use. Not a drug, supplement, or cosmetic. Sold exclusively to qualified research professionals and institutions.

About IGF-1 LR3
IGF-1 LR3 is a structural analog of native IGF-1, characterized in the published literature as a single-chain polypeptide of 83 amino acid residues. Researchers have characterized the molecule as differing from native IGF-1 in two ways: substitution of glutamic acid with arginine at position 3, and an additional 13-amino-acid sequence at the N-terminus. The peptide has an approximate molecular weight of 9111 Da. In the biochemical literature, these modifications have been described as reducing the affinity of the analog for insulin-like growth factor binding proteins (IGFBPs) relative to native IGF-1.

Research Background
IGF-1 LR3 has been referenced in in vitro and animal model studies examining the IGF-1 axis and its downstream signaling. The compound has been investigated as a research tool in cell culture systems — including myoblast and fibroblast lines — for studies of IGF-1 receptor (IGF-1R) binding and associated signaling pathways such as PI3K/Akt and MAPK. Comparative work in rodent models has examined the pharmacokinetic and biological profile of the LR3 analog versus native IGF-1, characterizing differences attributable to reduced IGFBP binding. The molecule has also been described in the literature as a reference compound in IGF-axis assay development. These references describe findings in non-human models and in vitro systems and do not constitute claims about effects in humans.