IGF 1 LR3 1mg Insulin Like Growth Factor 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 Exogenous IGF 1 promotes hair growth by stimulating cell proliferation and down regulating TGF 1 in C57BL 6 mice in vivo ScienceDirect Localized Igf 1 transgene expression sustains hypertrophy and regeneration in senescent skeletal muscle Nature Genetics