Insulin Like Growth Factor 1 (IGF 1) and Its Monitoring in Medical Diagnostic and in Sports IGF 1: Miracle Hormone or Health Hazard? Diet vs Disease Longitudinal infusion of a complex of insulin like growth factor I and IGF binding protein 3 in five preterm infants: pharmacokinetics and short term safety Pediatric Research 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 IGF 1 LR3 Muscle Growth & Performance The Biohacker Same molecule. Longer leash. IGF 1 LR3 is a long arginine 3 analog of insulin like growth factor 1. The Arg3 substitution prevents binding to IGFBP 3, the carrier protein that normally clears IGF 1 from circulation. Half life