Just over a year apart with 2 preps in between : r bodybuilding Insulin like growth factor 1 promotes cell cycle progression via upregulation of cyclin D1 expression through the phosphatidylinositol 3 kinase nuclear factor B signaling pathway in FRTL thyroid cells Acta Pharmacologica Sinica IGF 1 LR3 does not promote growth in late gestation growth restricted fetal sheep American Journal of Physiology Endocrinology and Metabolism American Physiological Society 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