MGF
Mechano Growth Factor (IGF-1Ec Splice Variant)
The exercise-induced IGF-1 splice variant for muscle repair
MGF (Mechano Growth Factor) is a splice variant of IGF-1 produced locally in muscle tissue in response to mechanical loading. It activates satellite cells that fuse with damaged muscle fibres.
Admin routes
Intramuscular
Popularity
Niche
Side effects
Generally mild
AU vendors
0 rated
✓Key benefits
📈What to expect
Enhanced post-workout pump and recovery reported by users
Localised muscle fullness and growth in injected areas
Based on community reports and published research. Individual results vary significantly.
💊Dosing protocols
Post-exercise muscle recovery (community protocol)
100-200 mcg
Injected into target muscle immediately post-workout
4-6 week cycles
Dosing information is sourced from published research and community protocols. This is not a recommendation. Consult a healthcare professional.
Research status|Preclinical - identified in human muscle, animal studies conducted
Overview
When you exercise, the IGF-1 gene in muscle tissue is spliced differently than the liver version, producing MGF (IGF-1Ec in humans, IGF-1Eb in rodents). MGF was identified by Geoffrey Goldspink at University College London. Its key role is activating muscle satellite cells, the stem cells that fuse with damaged muscle fibres to repair and grow them. Natural MGF has a very short half-life because it lacks the stabilising E-peptide extension. Synthetic MGF is available, though PEG-MGF (pegylated version) was developed to extend its duration of action.
⚙️How it works
MGF activates muscle satellite cells by binding to a receptor distinct from the IGF-1R. Once activated, satellite cells proliferate and differentiate, fusing with existing muscle fibres to donate their nuclei. More nuclei per fibre means greater protein synthesis capacity (the 'myonuclear domain' theory). MGF is produced as an initial pulse response to exercise-induced damage, followed by the liver-type IGF-1Ea which drives the later growth phase.
⚡Side effects
📅Research history
Goldspink identifies MGF as distinct from liver IGF-1 in muscle tissue
Goldspink publishes review on mechanical signals and IGF-1 splicing
MGF vs PEG-MGF
Unmodified MGF has a half-life of minutes due to rapid degradation. PEG-MGF adds a polyethylene glycol chain that extends the half-life to hours. The trade-off: MGF's short half-life means it acts locally at the injection site (useful for targeting specific muscles), while PEG-MGF circulates systemically. Goldspink's original research focused on the natural, short-acting form produced locally in muscle tissue.
References
- [1]Goldspink G. 'Mechanical signals, IGF-I gene splicing, and muscle adaptation.' Physiology, 2005.
- [2]Yang SY, Goldspink G. 'Different roles of the IGF-I Ec peptide (MGF) and mature IGF-I in myoblast proliferation and differentiation.' FEBS Letters, 2002.
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Disclaimer: This guide is for educational and informational purposes only. It is not medical advice. The dosing protocols listed are sourced from published research and community reports and do not constitute a recommendation. Always consult a qualified healthcare professional before using any peptide. Australian regulations classify many peptides as Schedule 4 (prescription-only) substances. Check current TGA guidelines before purchasing.