Muscle & Growth Hormone
MGF
Mechano Growth Factor · IGF-1Ec splice variant
What it is
MGF is a splice variant of IGF-1 that the body produces in response to mechanical loading (i.e., resistance training). It's released locally at the site of muscle damage and is believed to play a key role in satellite cell activation and muscle repair.
How it works
Stimulates dormant muscle satellite cells to proliferate and donate their nuclei to existing muscle fibers, allowing those fibers to grow larger. Half-life of native MGF is extremely short (~5 minutes) so injection timing is critical.
Benefits
- Local satellite cell activation
- Targeted muscle repair
- Theoretical hypertrophy support
Timeline
- Hours
- Local effect at injection site (very short window).
- Week 4–8
- Cumulative effects on targeted muscles.
Dosing & titration
Standard dose100–200 mcg per muscle group, immediately post-workout
Cycle length4–6 weeks
TimingWithin 30 minutes post-workout for best window
When to titrate upMost users prefer the PEGylated version (PEG-MGF) for convenience.
Side effects & risks
- Localized soreness
- Very limited human data
- Same cancer-risk caveats as IGF-1 family
Native MGF's short half-life makes it impractical. PEG-MGF is the more usable version for most.
Typical price
$60–$100/mo2 mg vial from a 503A compounding pharmacy.
Studies
- Goldspink G. Mechanical signals, IGF-I gene splicing, and muscle adaptation — Discoverer's review of MGF biology. PubMedPhysiology, 2005
- Search PubMed for MGF / IGF-1Ec — PubMed searchLive PubMed search
Educational reference only. Not medical advice.