Localized Igf 1 transgene expression sustains hypertrophy and regeneration in senescent skeletal muscle Nature Genetics RUO Recombinant Human IGF 1 LR3 Protein 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 Injecting IGF1 LR3 directly into the muscle your training : r nattyorjuice