Frontiers Sheep recombinant IGF 1 promotes organ specific growth in fetal sheep What is IGF 1 LR3?, Insulin Like Growth Factor 1 Long R3 (IGF 1 LR3) is a modified version of IGF 1 with a longer half life, making it significantly more potent and effective for muscle growth, ORF Genetics ISOkine IGF 1 LR3 Growth Factor IGF 1 LR3 does not promote growth in late gestation growth restricted fetal sheep American Journal of Physiology Endocrinology and Metabolism American Physiological Society 40 YEARS OF IGF1: Insulin like growth factors: actions on the skeleton in: Journal of Molecular Endocrinology Volume 61 Issue 1 (2018)