Long [R3] insulin-like growth factor-I (IGF-1 Long [R3]) by Bio-Peptide is a Human Recombinant, single, non-glycosylated, polypeptide chain containing 83 amino acids. It is an analog of human IGF-1 comprising the complete human IGF-1 sequence with the substitution of an Arginine (Arg or R) for the Glutamic Acid (Glu or E) at position 3 (hence R3), and a 13 amino acid extension peptide at the N-terminus.