Proper Use of IGF & MGF

When it comes to stimulating cell growth and promoting normal and balanced growth and development of muscle, cartilage, bone, liver, kidney, skin tissue, lungs, and nerves, there is hardly anything as potent as Insulin-like Growth Factor 1 or IGF-1.

The fact that use of IGF-1 is closely associated with burning of fat as a source of energy and it has the ability to inhibit insulin from transporting glucose across cell membranes means that it is an exceptional choice for sportsmen and bodybuilders who bridge between cycles. Since injected IGF-1 (also known as somatomedin C) does not enter the bloodstream,^[1] it cannot be detected by both blood and urine testing. This is something every sportsman would like to hear about a drug he or she is about to use or using.

Insulin-like growth factor 1 is commonly used as a diagnostic marker of the deficiency of growth hormone and for monitoring growth hormone replacement therapy.^[2] Locally administered IGF-1 has the potential of promoting wound repair in an estrogen-deprived animal model by dampening the local inflammatory response and promoting re-epithelialization. In addition to that, Insulin-like growth factor-I (IGF-I) functions as a mediator of GH-independent anabolic responses in many cells and tissues and the major mediator of growth hormone (GH)-stimulated somatic growth. It exerts its effects via activation of the IGF-I receptor that is widely distributed and enables blood-transported IGF-I to coordinate balanced growth among multiple tissues and organs. At physiologically relevant levels, IGF-1 blocks the cytotoxic action(s) of the antiestrogens 4-hydroxytamoxifen (4-OHT) and tamoxifen (TAM) when used as single agents or in a combination with the antiprogestin mifepristone (MIF) for treating estrogen receptor positive (ER+) breast cancer cells.^[3]

It is also known to promote cell survival by activating phosphatidylinositol 3-kinase (PI3K)/Akt kinase pathway and inducing the phosphorylation of endogenous FKHRL1 (a member of the Forkhead family of transcription factors possibly involved in cell cycle and apoptosis) in hippocampal neurons.^[4] It also tends to block the nuclear translocation of FKHRL1 in hippocampal neurons and promoted survival in parallel to the phosphorylation of Akt and FKHRL1. If that was not all, IGF-1 use is associated with providing extra glucose for the nervous system, preventing the signs of aging such as wrinkles, promoting the growth of new tissue, and supporting sexual performance. When used in dosages of 20-120 mcg per day, with or without meals for a period of fifty days of more and followed with a gap of thirty or forty days and then restarted again in the same doses, IGF-1 minimizes body fat, promotes lean muscle mass, improves skin tone, treats stunted growth or growth hormone deficiencies, improves the production of white blood cells, and repair nerve tissues besides promoting restful sleep and the sense of well being.^[5]

When produced and secreted, IGF-1 can circulate back to the hypothalamus and the pituitary to initiate the release of somatostain that completes the negative feedback loop and reduces the release of human growth hormone. It is found to be neuroprotective in animal models of focal brain ischemia and has the ability to improve neurological outcomes besides stimulating the regeneration of neural tissue. Moreover, it stimulates 5alpha-reductase, adrenal and gonadal androgen synthesis, androgen receptor signal transduction, lipogenesis, and sebocyte proliferation. IGF-1 is also well known for its ability to increase satellite cell activity, protein translation, and gene transcription and each of these processes prove beneficial to local and general muscle growth and can produce divergent effects on the hypertrophy response.^[6]

Mechano-growth factor (MGF), on the other hand, is a splice-variant of IGF-I sharing an identical mature region. It can produce rapid increases in strength and muscles to give it significant therapeutic and doping potential. MGF has the unique potential of activating the muscle stem cells and to start the process of tissue repair and hypertrophy processes. Studies in the past have indicated that Mechano-growth factor, an alternatively spliced variant of insulin-like growth factor 1 (IGF-1), is found to function independently from the rest of the molecule and demonstrated a neuroprotective effect in vivo and in vitro and the C-terminal peptide (MGF) has the potential to be developed into a therapeutic modality for the prevention of neuronal damage. Unlike mature Insulin-like growth factor-1, Mechano-growth factor inhibits terminal differentiation whilst increasing myoblast proliferation.

MGF can up-regulate heme oxygenase-1 (HO-1), which is an important cell defense mediator, and protects dopamine cells that could be beneficial in offering neuroprotection in Parkinson's disease. It was recently been identified as one of the most important insulin-like growth isoforms with regard to hypertrophy in response to a mechanical overload stimulus and plays an important role in skeletal muscle regeneration, as part of a cascade, in response to externally induced muscle damage. In addition to that, Mechano-growth factor also has the potential of activating muscle progenitor cells that provide the extra nuclei required for muscle hypertrophy, repair, and maintenance. It responds to changes in physiological conditions or environmental stimuli and expression of MGF is significantly increased in muscle, bone, and tendon after damage resulting from mechanical stimuli and in the heart and brain following ischemia.

The difference between IGF-1 and Mechano-growth factor is that MGF stimulates myoblasts division through stimulation of different receptors. MGF is used by professional sportsmen, especially those into bodybuilding, to accelerate growth of muscles, reducing fat mass of the body, increase endurance, strengthening bones, reducing levels of cholesterol, improving immune defense and skin, and accelerating recovery. Moreover, use of MGF has been associated with improvements in the context of hind limb muscle strength, motoneuron survival, and increase in motor unit. It also has the ability to stimulate localized muscle growth by leading to a response in the skeletal muscle when administered in an injectable form. It is expressed by mechanically overloaded muscles and its sequence differs from the systemic insulin-like growth factor-1 produced by the liver. The C-terminal peptide MGF is important for muscle repair and new cell growth, on the lines of IGF-1. This is the reason why sportsmen have been admiring it as it helps them with incredible body fat loss, fullness, increased pumps, and vascularity besides helping them gain 5-7 pounds of lean mass and losing 4-6 percent of body fat with just four weeks of MGF use.