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 IGF1 stimulates greater muscle hypertrophy in the absence of myostatin in male mice in: Journal of Endocrinology Volume 234 Issue 2 (2017) Localized Igf 1 transgene expression sustains hypertrophy and regeneration in senescent skeletal muscle Nature Genetics IGF 1 lr3 Dosage and Duration Guide. MuscleChemistry IGF 1 LR3: Benefits and Side Effects You Vita Bella Health