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Fitness & muscle

MGF

Muscle-specific IGF-1 isoform generated by mechanical stress; promotes local muscle repair and satellite cell activation.

Research compound Fitness & muscle Recovery & healing

Reviewed 2026-09-12
Full name
Mechano Growth Factor (IGF-1Ec splice variant)
Also known as
mechano growth factor, IGF-1Ec
Regulatory status
Research compound | Experimental use
Variant note
PEG-MGF is a pegylated variant with extended half-life (minutes to hours) enabling more systemic distribution beyond the injection site, versus native MGF's local/periosteal action. Dosed similarly but with enhanced systemic bioavailability.

Origin

IGF-1 splice variant produced locally in muscle after mechanical loading or injury, first described by Goldspink in the 1990s. Unlike systemic hepatic IGF-1, it acts autocrine/paracrine, right where it's made.

Mechanism

Binds IGF-1 receptor on satellite cells, driving proliferation, differentiation, and fusion into myofibers via PI3K-Akt and MAPK-ERK signaling. First responder to muscle damage.

Research summary

Evidence

Mechanistic work is mostly preclinical, animal and cell culture. Human trials of exogenous MGF are close to nonexistent. Compounding pharmacies sell it for experimental use, but human efficacy and safety are poorly characterized.

Evidence tier: Research compound — see the methodology note for how this is assessed.

Citations

No specific peer-reviewed citations indexed for this entry — see the research summary above for what evidence does exist.

Reported benefits

  • local muscle hypertrophy
  • muscle repair and recovery
  • satellite cell activation

Dosing protocols reported in the literature & community

These are protocols reported by compounding pharmacies, published trials, or self-experimentation communities — not a prescription. Start low, especially for anything new.

Reported dosing protocols
RouteReported protocol
Local subcutaneous/intramuscular injection100-200 mcg injected near target muscle post-workout, 2-3x weekly.

Side effects

  • local inflammation at injection site
  • bruising
  • potential systemic hypoglycemia if absorbed systemically

Safety notes

Safety: Not FDA-approved, minimal human trial data. Theoretical concern: exogenous IGF-1 pathway activity could feed occult malignancy growth, though this is speculative.
Community & reddit notes (anecdotal — not clinical evidence)

Used post-workout for recovery. The local-MGF vs systemic PEG-MGF distinction matters for timing and use case.

Mixing compatibility

Pulled from a community-charted mixing-compatibility reference (anecdotal, clinic-use, and community-reported signals) — not a safety guarantee. Verify independently before combining anything.

Used together in wellness-clinic protocols

Reported as a combination to avoid