Description
What it is
IGF-1 LR3 (Long R3 IGF-1) is not a short synthetic peptide but a small recombinant protein of 83 amino acids, roughly 9.1 kDa, an engineered analogue of native human IGF-1 (70 residues). Two modifications define it: an arginine-for-glutamate swap at position 3 (Glu3Arg), the R3, and a 13-residue N-terminal extension attributed to the human proinsulin B chain, the Long. Reported formula C400H625N111O115S9, observed mass near 9111 Da (CAS 946870-92-4).
Research context
At the receptor level IGF-1 LR3 is characterised as an IGF-1 receptor (IGF1R) agonist whose two modifications sharply reduce binding to the IGF binding proteins (IGFBPs), so more of the molecule remains free in solution. Its long-established, genuine laboratory use is as a potent IGFBP-resistant cell-culture growth supplement, for example in CHO and stem-cell culture. AxYn supplies it in that reference-reagent context for in-vitro laboratory investigation only, with no physique or performance framing.
11 studies indexed on PubMed (NIH) for IGF-1 LR3 as of August 2026. A measure of research volume only, not a claim of efficacy.
Handling and storage
Supplied as a lyophilised protein for reconstitution with bacteriostatic or sterile water as a research-handling step only. Store the sealed vial cold and protected from light. As a folded, disulfide-bonded protein it is sensitive to heat, oxidation and pH extremes, so keep reconstituted material cold, aliquot before freezing and avoid repeated freeze-thaw.
Testing and quality
Because it is a folded protein, batch testing pairs HPLC purity with mass spectrometry near 9111 Da and an identity note distinguishing it from native IGF-1 and related analogues, rather than a purity number alone. A Certificate of Analysis (CoA) accompanies each batch. Supplied for laboratory research use only. Not for human or animal consumption.
Specification
Frequently asked questions
Research handling and related compounds
New to handling lyophilised material? See our reconstitution guide, the storage and shelf-life guide, and how to read a Certificate of Analysis.
Related research compounds in Growth Factors & Muscle: Follistatin 344.
Reviews
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