Peptides for Bodybuilding Peptide Stack for Putting On Lean Mass 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 Saluta 1.2G Easemart AhR in biological processes of adipocytes and lipid metabolism in obesity: Friend and foe ScienceDirect