IGF 1 LR3 in Aesthetic and Anti Aging Medicine: Benefits and Risks Hubmed Pediatric Implications of Normal Insulin GH IGF Axis Physiology Endotext NCBI Bookshelf 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 Huma Peptide IGF 1 LR3 Lean Muscle Growth & Recovery Frontiers Growth hormone insulin like growth factor I axis in health and disease states: an update on the role of intra portal insulin