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 IGF 1 inhibits inflammation and accelerates angiogenesis via Ras PI3K IKK NF B signaling pathways to promote wound healing ScienceDirect Localized Igf 1 transgene expression sustains hypertrophy and regeneration in senescent skeletal muscle Nature Genetics Insulin like growth factor 1 stimulates retinal cell proliferation via activation of multiple signaling pathways ScienceDirect