IGF 1 LR3 The Muscle Building Peptide Everyone's Talking About IGF 1 LR3 is one of the most powerful performance peptides used for muscle growth, recovery, and fat loss. It's a modified version A Medical Review of IGF 1 LR3 Dosage, Side Effects and Safety Aspects IGF 1 LR3 does not promote growth in late gestation growth restricted fetal sheep American Journal of Physiology Endocrinology and Metabolism American Physiological Society LONG R IGF I Theres a lot of confusion around peptides and muscle., Heres how I actually think about it., Most peptides dont build muscle directly., They improve the systems that allow muscle to grow., First,