Localized Igf 1 transgene expression sustains hypertrophy and regeneration in senescent skeletal muscle Nature Genetics Can peptides like sermorelin, IGF 1 LR3, and GHS boost muscle growth? Maybe. Are they safe? We don't know. These compounds boost natural growth hormone (GH) and IGF 1 levels, key drivers of muscle Gut derived IL 13 contributes to growth via promoting hepatic IGF 1 production Microbiome Springer Nature Link Awesome results this year igf 1 lr3 ,cyp,e,primo then adding tren for 2 months then removed primo and tren added FTPP and diaing diet with labs and results hopefully helps : r Peptides Just over a year apart with 2 preps in between : r bodybuilding