IGF-1 (Insulin Like Growth Factor 1 a.k.a. somatomedin C)

Quick info about IGF-1 (Insulin Like Growth Factor 1 a.k.a. somatomedin C)

IGF1 is a polypeptide hormone about the same size as insulin, or 70 amino acids; it's a member of the "super family." It's a highly anabolic hormone released primarily in the liver (but also in peripheral tissues) with the stimulus of Growth Hormone (GH). It is responsible for much of the anabolic activity of GH, including nitrogen retention and protein synthesis as well as muscle cell hyperplasia (increase in number of muscle cells), as well as mitogenesis (the growth of new muscle fibers). As with all anabolic substances, IGF-1's anabolic effects are still limited only by the protein (amino acid) supply within muscle cells. Thus, as you may expect, IGF works much better when you are eating enough protein.

Also of note, and of special interest to both athletes and bodybuilders who are rehabbing an injury is that IGF is vital to the proper production of connective tissue, and exogenous IGF administration may improve collagen formation and aid in the repair of cartilage. You will lose more fat and gain more muscle when you combine GH and IGF-1 than you would using either alone. The subjects in this study, over 12 weeks gained around 3kgs of lean mass, and lost around 2kgs of fat. 

So how much IGF do we use? The most popular type available on the Black Market right now is Lr3igf-1 (Long R3 Insulin-like Growth Factor-I or Long R3IGF-I) which is an 83 amino acid analog of human IGF-I comprising the complete human IGF-I sequence with the substitution of an Arg for the Glu at position 3, as well as a 13 amino acid extension peptide at the N-terminus.