MGF
Mechano Growth Factor — IGF-1 Splice Variant
What is MGF?
MGF (Mechano Growth Factor) is a splice variant of IGF-1 that is produced locally in muscle tissue in response to mechanical load (exercise-induced damage). It is the initial GF signal that activates satellite cells (muscle stem cells) after training-induced muscle damage, before IGF-1 Ea takes over for systemic repair.
MGF activates quiescent satellite cells by binding a distinct receptor from the main IGF-1 receptor, triggering them to proliferate and differentiate into new muscle fibers. Its action is local and immediate — produced at the site of muscle damage within hours of exercise. PEGylated MGF (PEG-MGF) has a longer half-life (~30 min vs ~2 min for native MGF) and is the injectable form used in community protocols.
Research Evidence
Well-characterized local satellite cell activation mechanism in animal models. MGF is established as the primary initiator of muscle repair after mechanical load.
Community use for muscle growth is widespread, typically injected bilaterally into worked muscle groups post-exercise. No controlled injectable human trials.
Evidence grades: Gold = RCT human data · Silver = consistent animal/human data · Bronze = limited or preliminary
Dosing Protocols
Reconstitution Guide
| Vial Size | BAC Water | Concentration | Target draw |
|---|---|---|---|
| 2 mg | 2 ml | 1 mg/ml | 200mcg = 20 units |
| 5 mg | 5 ml | 1 mg/ml | 200mcg = 20 units |
Frequently Asked Questions
What is the difference between MGF and IGF-1 LR3?
MGF is the acute local signal that activates satellite cells immediately after muscle damage. IGF-1 LR3 is the systemic anabolic signal that drives protein synthesis and growth across all tissues. MGF initiates the repair process; IGF-1 LR3 drives the growth phase. Many protocols use both: MGF post-workout to activate satellite cells, IGF-1 LR3 on training days for systemic anabolism.
Is MGF detectable in drug testing?
Yes. MGF and its variants are on the WADA prohibited list as peptide hormones. Prohibited in all competitive sports governed by WADA.
References
- [1]Yang SY, Goldspink G. Different roles of the IGF-I Ec peptide (MGF) and mature IGF-I in myoblast proliferation and differentiation. FEBS Lett. 2002;522(1-3):156-160.
- [2]Goldspink G. Loss of muscle strength during aging studied at the gene level. Rejuvenation Res. 2007;10(3):397-405.
This profile was prepared using AI-assisted research synthesis. Citations are provided where applicable — verify with primary sources before clinical application.
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