Mechano Growth Factor (MGF) also known as IGF-1Ec is a growth factor/repair factor that is derived from exercised or damaged muscle tissue. It's called MGF as IGF-IEa is a bit of a mouthful and harder to identify amongst the other IGF variants. What makes MGF special is its' unique role in muscle growth. MGF has the ability to cause wasted tissue to grow and improve by activating muscle stem cells and increasing the upregulation of protein synthesis, this unique ability can rapidly improve recovery and speed up muscle growth. MGF can initiate muscle satellite (stem) cell activation in addition to its IGF-1 receptor domain which, in turn, increases protein synthesis turnover; therefore, if used correctly it can improve muscle mass over time. The liver produces 2 kinds of MGF splice variants of IGF 1) IGF-1Ec: This is the first phase release igf splice variant and it appears to stimulate satellite cells into activation, This is the closest variant to synthetic MGF. 2) Liver type IGF-IEa: this is the secondary release of igf from the liver, and its far less anabolic. mgf vs IGF-IEa Fig 1. MGF vs. IGF-IEa MGF differs from the second variant IGF-IEa as it has a different peptide sequence which is responsible for replenishing the satellite cells in skeletal muscle; in other words, it is more anabolic and longer acting than the systematic release of the second MGF liver variant. So just think of MGF as a highly anabolic variant of igf. After you have trained, the IGF-I gene is spliced towards MGF then that causes hypertrophy and repair of local muscle damage by activating the muscle stem cells as well as other important anabolic processes, including the above mentioned protein synthesis, and increased nitrogen retention. In rats, some studies have shown muscle mass increases of 20 percent from a single MGF injection, but somehow I think many of these studies are not accurate, however the potential is undeniable.