Mechano Growth Factor MGF (mechano growth factor) has been used by bodybuilders and athletes for a few years. After strength training, IGF-1 is released within the muscle. Specifically, at this time immediately after mechanical use of a muscle, the IGF-I gene is spliced toward MGF which initiates hypertrophy and repair of local muscle damage. This occurs both by activating muscle stem cells and satellite cells, but also via various other anabolic processes. It differs from normal IGF-1 primarily because of its C-terminal sequence. In a rodent study, a single intramuscular injection into the muscle resulted in a 25% increase in mean muscle fiber cross-sectional area within three weeks. Using a similar protocol, liver-derived IGF-1 took four months to produce a 15% increase. It also appears that in relation to age, the young have a better ability to respond to MGF, and that the elderly experience a reduced MGF response, which leads to a reduced ability to stimulate the growth of new muscle tissue. For research use only.