IGF-1 LR3 (Insulin-like Growth Factor 1 Long Arginine 3, 1mg) is a synthetic 83-amino acid analog of native IGF-1 incorporating two structural modifications: an arginine substitution at position 3 (Glu3 to Arg3) and a 13-amino acid N-terminal extension. Together these modifications substantially reduce binding affinity for IGF binding proteins (IGFBPs), extending the compound’s circulating half-life from the minutes characteristic of native IGF-1 to approximately 20 to 30 hours — while preserving full IGF-1 receptor binding affinity. It is studied in laboratory settings for IGF-1R signaling research, satellite cell activation, skeletal muscle biology, and cell proliferation pathway investigation. Manufactured in a cGMP-certified US facility. Independently third-party tested for HPLC purity, mass spectrometry identity, endotoxin, and sterility. For laboratory research use only.