MGF
Growth factor splice variant · Also known as Mechano Growth Factor, IGF-1Ec, MGF Peptide
What is MGF?
A naturally occurring splice variant of IGF-1 produced locally in muscle tissue after mechanical stress. It activates satellite cells for muscle repair but has a half-life of only minutes without PEGylation.
MGF (mechano growth factor) is the product of an alternative splicing event of the IGF-1 gene that occurs in response to muscle damage from exercise or injury. Unlike systemic IGF-1, MGF acts locally to activate muscle satellite cells, the stem cells responsible for muscle repair and hypertrophy.
Benefits & evidence
How it works
When muscle fibers are mechanically stressed (resistance training, stretching, injury), the IGF-1 gene undergoes alternative splicing to produce MGF instead of the standard IGF-1Ea isoform.
MGF has a unique C-terminal E domain that activates satellite cells (muscle stem cells) to proliferate but not yet differentiate. This expands the pool of repair cells available. The standard IGF-1Ea isoform, produced later, then signals these expanded satellite cells to differentiate and fuse with damaged muscle fibers.
Native MGF is rapidly degraded by proteases, giving it a half-life of just a few minutes. This is why PEG-MGF was developed, though some researchers prefer the native form for its localized, pulsatile action at injection sites.
Dosing information
Typical dosing protocol
100-200 mcg
Post-workout200 mcg
Post-workout, 2-3x per weekInjected locally into the trained muscle immediately post-workout when natural MGF production peaks. The very short half-life means timing matters.
Side effects
Most side effects tend to improve as your body adjusts.