Human Recombinant IGF I LR3, ACF STEMCELL Technologies IGF 1 LR3 does not promote growth in late gestation growth restricted fetal sheep American Journal of Physiology Endocrinology and Metabolism American Physiological Society 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, IGF 1 LR3: A peptide for muscle gains Jay Campbell posted on the topic LinkedIn IGF 1 LR3 Injection Benefits And How It Works The HCG Institute