IGF stands for insulin-like growth factor. It is a natural substance that is produced in the human body and is at its highest natural levels during puberty. During puberty IGF is the most responsible for the natural muscle growth that occurs during these few years. There are many different things that IGF does in the human body; I will only mention the points that would be important for physical enhancement. Among the effects the most positive are increased amino acid transport to cells, increased glucose transport, increased protein synthesis, decreased protein degradation, and increased RNA synthesis.
When IGF is active it behaves differently in different types of tissues. In muscle cells proteins and associated cell components are stimulated. Protein synthesis is increased along with amino acid absorption. As a source of energy, IGF mobilizes fat for use as energy in adipose tissue. In lean tissue, IGF prevents insulin from transporting glucose across cell membranes. As a result the cells have to switch to burning off fat as a source of energy.
IGF also mimic’s insulin in the human body. It makes muscles more sensitive to insulin’s effects, so if you are a person that currently uses insulin you can lower your dosage by a decent margin to achieve the same effects, and as mentioned IGF will keep the insulin from making you fat.
Perhaps the most interesting and potent effect IGF has on the human body is its ability to cause hyperplasia, which is an actual splitting of cells. Hypertrophy is what occurs during weight training, it is simply an increase in the size of muscle cells. See, after puberty you have a set number of muscle cells, and all you are able to do is increase the size of these muscle cells, you don’t actually gain more. But, with IGF use you are able to cause this hyperplasia which actually increases the number of muscle cells present in the tissue, and through weight training and steroid usage you are able to mature these new cells, in other words make them grow and become stronger. So in a way IGF can actually change your genetic capabilities in terms of muscle tissue and cell count. IGF proliferates and differentiates the number of types of cells present. At a genetic level it has the potential to alter an individuals capacity to build superior muscle density and size.
There is a lot of talk about the similarity between IGF and growth hormone. The most often asked question is simply which is more effective. GH doesn’t directly cause your muscles to grow, it works very indirectly by increasing protein synthesis capabilities. GH also indirectly causes muscle growth by stimulating the release of IGF when it (the GH) is destroyed in the human body. So one way you could look at it as GH being a precursor to IGF. So to put it simple IGF is more effective at directly causing muscle growth and density increases. IGF is also much more cost effective.
The most effective form of IGF is Long R3 IGF-1, it has been chemically altered and has had amino acid changes which cause it to avoid binding to proteins in the human body and allow it to have a much longer half life, around 20-30 hours.
“Long R3 IGF-1 is an 83 amino acid analog of IGF-1 comprising the complete human IGF-1 sequence with the substitution of an Arg(R) for the Glu(E) at position three, hence R3, and a 13 amino acid extension peptide at the N terminus. This analog of IGF-1 has been produced with the purpose of increasing the biological activity of the IGF peptide.”
“Long R3 IGF-1 is significantly more potent than IGF-1. The enhanced potency is due to the decreased binding of Long R3 IGF-1 to all known IGF binding proteins. These binding proteins normally inhibit the biological actions of IGF’s.”