PEG-MGF 2mg

Mechano growth factor is not a separate gene product. It is a splice variant of the human IGF1 gene — IGF-1Ec (UniProt P05019-4) — and the peptide sold as MGF is the 24-residue C-terminal fragment of that variant’s E-domain propeptide, the portion cleaved away and discarded when IGF-1 matures. The reference human sequence is Tyr-Gln-Pro-Pro-Ser-Thr-Asn-Lys-Asn-Thr-Lys-Ser-Gln-Arg-Arg-Lys-Gly-Ser-Thr-Phe-Glu-Glu-Arg-Lys (YQPPSTNKNTKSQRRKGSTFEERK), as registered in UniProt, RefSeq NP_001104753.1, and the FDA substance registry under UNII Q86M4KXC2P. Worth knowing: material analyzed from circulation has repeatedly been found to differ from that reference. Analytical laboratories examining material obtained from circulation have characterized a C-terminally amidated analog (Esposito et al., Rapid Communications in Mass Spectrometry 2012, PMID 22328223) and an arginine-to-histidine substitution at position 23, designated MGF R23H (Cox et al., Drug Testing and Analysis 2017, PMID 28035768; see also Thevis et al., Growth Hormone & IGF Research 2014, PMID 25466910). "MGF" is therefore a name covering several distinct molecules rather than one defined substance.

On the PEGylation itself, the honest position is that almost nothing is published. A full-text search of the peer-reviewed literature returns no study characterizing PEG-MGF as a substance; public substance registries hold records for unmodified MGF and its C-terminal amide but none for a PEGylated form; and across three independent laboratories that analyzed real "MGF" products with high-resolution mass spectrometry, no PEGylated form was found or characterized. Consequently there is no published PEG chain length, no established attachment site, no confirmed mass, and no pharmacokinetic data of any kind. The general rationale for PEGylating a peptide — extending circulating half-life and slowing proteolysis and renal clearance — is well established for other molecules, but it has not been measured for this one, and a 2026 review notes explicitly that effects observed with native IGF-1Ec or isolated E-domain peptides cannot be assumed to carry over to PEG-conjugated constructs (PMID 42395176).

The research on unmodified MGF is in vitro and animal work. The E-domain variant was originally cloned from stretched rabbit muscle (Yang et al., Journal of Muscle Research and Cell Motility 1996, PMID 8884603), and a rat study reported that MGF messenger RNA rises rapidly after muscle damage and then falls as another isoform rises, a time course the authors interpreted as consistent with satellite-cell activation (Hill & Goldspink, Journal of Physiology 2003, PMID 12692175) — a temporal correlation rather than a causal demonstration. The synthetic 24-mer has been reported to increase myoblast proliferation while inhibiting terminal differentiation in cell culture (Yang & Goldspink, FEBS Letters 2002, PMID 12095637). Two caveats belong with all of this. The frequently repeated claim that the E-peptide acts independently of the IGF-1 receptor is contested rather than settled: it is supported by antibody-blockade and receptor-knockdown work (PMID 12095637; PMID 20844834) and directly rebutted by an independent laboratory whose paper is titled to that effect (Brisson & Barton, PLoS One 2012, PMID 23029120). And the endogenous free peptide has never actually been isolated from cells, tissue, or biological fluid — a point made in a 2010 review in Endocrinology (PMID 20130113) and conceded in a review co-authored by the originating group.

Neither MGF nor PEG-MGF is an approved drug. This product is supplied strictly for in vitro and laboratory research and is not for human or veterinary use.