IGF 1 LR3 (Insulin like Growth Factor 1 Long R3) is often called the "Holy Grail" of muscle building peptides because of its potent anabolic effects. In a Med Spa context, it is typically sought out IGF 1 LR3 Peptide and Muscle Development 40 YEARS OF IGF1: Insulin like growth factors: actions on the skeleton in: Journal of Molecular Endocrinology Volume 61 Issue 1 (2018) Switched things up and have been using my IGF 1 LR3 30 mins pre workout and have been noticing longer lasting pumps and more vascularity so far! 2 more weeks until I cycle