If your goal is better body composition, that means more muscle and less fat, certain peptides can help. These are not steroids and they do not replace testosterone if testosterone is low. IGF 1 LR3 and Penis Enlargement: What the Evidence Actually Shows Gibco Human IGF I LR3 Recombinant Protein, PeproTech Organ weights in response to Long R3 insulin like growth factor 1 (LR3 Download Scientific Diagram IGF 1 Therapy Improves Muscle Size and Function in Experimental Peripheral Arterial Disease ScienceDirect