Peptide Therapy 101: A Complete Beginner's Guide Vitality Health Peptide Synthesis Polaris Peptides IGF LR3 is a peptide that play a role in muscle growth, tissue repair and recovery. But like all peptide therapies, it's not one size fits all. We focus on using peptides thoughtfully and in the IGF 1 LR3 does not promote growth in late gestation growth restricted fetal sheep American Journal of Physiology Endocrinology and Metabolism American Physiological Society IGF 1 LR3 vs GH Peptides The Battle Between Performance & Risk