MGF

Last Updated: July 2026

MGF (Mechano Growth Factor) is the IGF-1Ec splice variant of the insulin-like growth factor 1 (IGF-1) gene — specifically its unique 24-amino-acid C-terminal "E-peptide." Unlike liver-derived systemic IGF-1, MGF is produced locally in mechanically stressed or damaged skeletal muscle (and cardiac muscle and bone), acting as an autocrine/paracrine early-repair signal. It is not approved and is supplied for research use only.

What is MGF and how does it differ from regular IGF-1?

The IGF-1 gene is alternatively spliced into isoforms that share the same mature IGF-1 peptide but carry different C-terminal E-peptide extensions; MGF (IGF-1Ec) is the mechano-responsive variant, expressed in muscle after loading or injury rather than circulating from the liver like IGF-1Ea. Its distinguishing feature is that local expression tied to mechanical stress. Compare the related IGF-1 LR3 and IGF-1 DES profiles.

How does MGF work?

The classic finding (Yang and Goldspink, 2002) is that the MGF E-peptide alone can activate quiescent satellite (muscle stem) cells and promote their proliferation — apparently through a mechanism not blocked by IGF-1-receptor antibodies — while mature IGF-1 drives the later differentiation step; this "two-phase" model puts MGF first in the repair cascade. Because the unmodified E-peptide degrades within minutes, a PEGylated form (PEG-MGF) was developed for research use.

What does the research on MGF show?

Evidence is preclinical: MGF activates satellite cells and is rapidly upregulated in damaged muscle and in cardiac tissue after myocardial infarction, with neuroprotective signals in models of cerebral ischemia; aged muscle shows a blunted MGF response. There are no controlled human efficacy trials. Evidence level: Preclinical only.

What are the safety concerns and regulatory status?

MGF is not approved for human use, has no established human safety profile, and is prohibited in sport (WADA). See the legal status guide.

Why does vendor verification matter, and how does Peptigrity verify?

"MGF" and "PEG-MGF" are distinct products with very different half-lives, and short peptides are easily mislabeled — HPLC purity and mass-spec identity are the objective checks. Peptigrity buys it anonymously, tests it at independent ISO-accredited labs, and publishes the unedited COA; the trust score weights lab purity and reviews equally (50/50). See how to read lab results.

Educational information only; not medical advice. MGF is not approved for human use. Consult a qualified healthcare provider. Peptigrity does not sell, endorse, or recommend products or vendors.