PeptideCompareMGF — EU research guide.
MGF (Mechano Growth Factor) is a splice variant of IGF-1 produced in skeletal muscle in response to mechanical loading. Its unique E-domain peptide activates muscle stem cells (satellite cells) independently of the IGF-1 receptor.
What is MGF?
MGF is produced when mechanical stress on skeletal muscle fibres causes alternative splicing of the IGF-1 pre-mRNA, inserting a 52-nucleotide sequence that shifts the reading frame and produces a unique C-terminal E-domain peptide. This MGF E-domain peptide acts through a receptor distinct from IGF-1R to activate quiescent muscle satellite cells — the stem cells responsible for muscle repair and hypertrophy.
What does the research show?
Local injection in animal models shows activation of satellite cells, myoblast proliferation and enhanced muscle repair after injury. The native peptide has an extremely short half-life (minutes), leading to the development of PEG-MGF for research requiring systemic delivery. MGF and IGF-1 LR3 have complementary mechanisms — MGF activates satellite cells; IGF-1 LR3 drives differentiation and protein synthesis.
EU legal status
Not approved anywhere. WADA-prohibited (S2). Available for muscle biology and satellite cell research only.
Molecular information
Pharmacokinetics
MGF across EU suppliers
COA-verified EU vendors · Updated monthly
References
- The foundational claim: a synthetic 24-amino-acid C-terminal E-peptide activates muscle satellite cells independently of the IGF-1 receptor. Almost everything marketed about MGF traces back to this single mechanism paper. Yang SY, Goldspink G. FEBS Lett. 2002;522(1–3):156–160. PubMed 12095637
- The note that vendor pages leave out: researchers at two pharmaceutical companies tried to reproduce the MGF E-peptide effect on human and mouse myoblasts and found no apparent effect on proliferation or differentiation. A key claimed mechanism did not replicate — the most decision-relevant fact about this peptide. Fornaro M, et al. Am J Physiol Endocrinol Metab. 2014;306(2):E150–E156. PubMed 24253048
- A counterweight to that null result: in isolated human muscle cells the 24-aa E-peptide extended the proliferative lifespan of satellite cells from young donors but not from old ones. The literature is genuinely mixed, which is the honest summary — not the uniform picture usually presented. Kandalla PK, Goldspink G, Butler-Browne G, Mouly V. Mech Ageing Dev. 2011;132(4):154–162. PubMed 21377485