Serum Insulin like Growth Factor 1 Is a Biomarker of Testosterone Production and Intact Acrosome in Asian Elephants (Elephas maximus) 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, IGF 1: Miracle Hormone or Health Hazard? Diet vs Disease Frontiers Sheep recombinant IGF 1 promotes organ specific growth in fetal sheep IGF 1 LR3 Huma Peptide