IGF 1 LR3 Peptide Therapy Muscle Growth & Recovery Esthetic Solutions IGF 1 LR3 Peptide and Muscle Development Organ weights in response to Long R3 insulin like growth factor 1 (LR3 Download Scientific Diagram human IGF 1 LR3 protein 1000 g Human E. coli ReliaTech GmbH algorx IGF 1 LR3 (Insulin like Growth Factor 1 Long R3) is often called the "Holy Grail" of muscle building peptides because of its potent anabolic effects. In a Med Spa context, it is typically sought out