Illicit Use of Steroids Recombinant expression of IGF 1 and LR3 IGF 1 fused with xylanase in Pichia pastoris Applied Microbiology and Biotechnology Springer Nature Link IGF 1 LR3 The Muscle Building Peptide Everyones Talking About , IGF 1 LR3 is one of the most powerful performance peptides used for muscle growth, recovery, and fat loss. Its a modified version INCRELEX (mecasermin) for Severe IGF 1 Deficiency IGF 1 LR3 does not promote growth in late gestation growth restricted fetal sheep American Journal of Physiology Endocrinology and Metabolism American Physiological Society