IGF-1 LR3 (Long R3 IGF-1) is an engineered analog of insulin-like growth factor 1, built with an arginine substitution at position 3 and a 13-amino-acid N-terminal extension (83 amino acids total). These changes sharply reduce its affinity for IGF binding proteins while preserving affinity for the type 1 IGF receptor. At a molecular weight of approximately 9117.6 g/mol, it is a well-documented cell-culture reagent used to increase receptor bioavailability in serum-free and low-serum culture systems.
Research on LR3 is laboratory and cell-culture research, not human or animal trial data. It is used in cell-culture supplementation and recombinant protein production research, including CHO cell line systems, where its reduced IGF binding protein affinity keeps more of the molecule available to reach the receptor on cultured cells.
Each Etched Research vial contains 1mg of lyophilized powder.
Specifications:
– Molecular Formula: C400H625N111O115S9
– Molecular Weight: ~9117.6 g/mol
– CAS: 946870-92-4
– Form: Lyophilized powder
– Storage: -20°C (lyophilized); 4°C once reconstituted, use within 30 days
FOR IN VITRO RESEARCH USE ONLY. NOT FOR HUMAN CONSUMPTION, INGESTION, OR ANY IN VIVO USE.
- What it is: An engineered version of IGF-1, modified specifically to work better as a cell-culture reagent, not a molecule studied in humans or animals.
- Researchers have used it for: supplementing serum-free and low-serum cell cultures, including in recombinant protein production research.
- Evidence level: Real, but narrow. This is laboratory and cell-culture research, not human or animal trial data. Those are different kinds of evidence.
- The short version: IGF-1 LR3 has a genuine, well-documented role in lab science, as a tool for growing cells in a dish. It has no published human trial history. This is a research summary, not a reason to use anything.
