Before and After Igf1 Lr3 TikTok IGF 1LR3 Apollo Peptide Sciences There's a lot of confusion around peptides and muscle. Here's how I actually think about it. Most peptides don't build muscle directly. They improve the systems that allow muscle to grow. First, Attenuated glucose stimulated insulin secretion during an acute IGF 1 LR3 infusion into fetal sheep does not persist in isolated islets Journal of Developmental Origins of Health and Disease Cambridge Core