PEG-MGF

Overview

PEG-MGF is the pegylated form of Mechano Growth Factor (MGF), the distinct 24-amino-acid C-terminal E-peptide encoded by the IGF-1Ec splice variant (IGF-1Eb in rodents) that is transiently upregulated in muscle after mechanical loading or damage. MGF is related to but pharmacologically distinct from mature IGF-1 and IGF-1 LR3. Pegylation extends its half-life from minutes to several hours, and the compound is marketed as a research chemical for muscle repair protocols. It is not FDA-approved for any indication.

Mechanism of Action

The MGF E-peptide acts locally on muscle satellite (stem) cells, promoting their proliferation and delaying terminal differentiation, which expands the progenitor pool available for fusion into damaged myofibers. Receptor-blocking studies by Yang & Goldspink (2002) indicated that the E-peptide acts through a receptor distinct from the classical IGF-1R, although the exact receptor remains unconfirmed — this is one reason MGF is mechanistically separable from mature IGF-1 or IGF-1 LR3. Conjugation of polyethylene glycol to the peptide reduces renal clearance and proteolysis, extending plasma half-life from minutes (native MGF) to several hours.

Research Summary

Yang and Goldspink (FEBS Lett 2002, PMID 12095637) established that the MGF E-peptide promotes myoblast proliferation and delays terminal differentiation through a receptor distinct from IGF-1R, separating MGF pharmacology from mature IGF-1. Kandalla et al. (Mech Ageing Dev 2011, PMID 21354439) showed the 24-aa MGF E-peptide activates human muscle progenitor cells and enhances their fusion potential even from older donors. Qin et al. (Mol Cell Biochem 2012, PMID 22875667) confirmed MGF drives satellite-cell proliferation while inhibiting differentiation by down-regulating MyoD and p21. Comprehensive reviews by Matheny, Nindl & Adamo (Endocrinology 2010, PMID 20130113) and Zabłocka, Goldspink et al. (Front Endocrinol 2012, PMID 23125840) summarize the evidence across muscle, cardiac and neural tissue and caution that MGF's receptor, in vivo pharmacokinetics, and safety profile remain incompletely characterized. No randomized controlled human trials of PEG-MGF have been published. MGF and IGF-1 analogs are prohibited at all times under the WADA Code.

Vendors selling PEG-MGF

Scored vendors carrying PEG-MGF, ranked by trust grade. Grades are computed from indexed Certificates of Analysis. Full $/mg pricing is on the comparison page.

Prescribers who offer PEG-MGF

3 prescribers in our directory work with PEG-MGF, each confirmed from their own website. Peptides like PEG-MGF require a prescription from a licensed provider.

Reported Side Effects

• Injection-site pain, erythema, or swelling
• Localized muscle soreness
• Theoretical mild hypoglycemia (minimal with localized dosing due to MGF's local rather than systemic IGF-1R activity)
• Unknown long-term effects — no human safety data

Compare PEG-MGF with Others

Research References

• Different roles of the IGF-I Ec peptide (MGF) and mature IGF-I in myoblast proliferation and differentiation (Yang & Goldspink, FEBS Lett 2002) (2002)
• Mechano Growth Factor E peptide (MGF-E) activates human muscle progenitor cells and increases their fusion potential at different ages (Kandalla et al., Mech Ageing Dev 2011) (2011)
• Minireview: Mechano-growth factor: a putative product of IGF-I gene expression involved in tissue repair and regeneration (Matheny et al., Endocrinology 2010) (2010)
• Mechano-Growth Factor: an important cog or a loose screw in the repair machinery? (Zabłocka et al., Front Endocrinol 2012) (2012)
• MGF promotes proliferation and inhibits differentiation of porcine satellite cells by down-regulation of key myogenic transcription factors (Qin et al., Mol Cell Biochem 2012) (2012)

Frequently asked questions

Has PEG-MGF been independently lab-tested?

Disclosed Labs has collected 12 Certificates of Analysis (COA) for PEG-MGF from 5 independent testing labs. 8 vendors have submitted material for testing. Products average 99.6% tested purity across the corpus. Full testing data is available at https://www.disclosedlabs.com/peptides/peg-mgf/testing.

What is the average purity of PEG-MGF on the market?

Based on 12 COAs analyzed by Disclosed Labs, PEG-MGF products average 99.6% (±0.3%) tested purity. Individual vendor results vary; see per-vendor COA data at https://www.disclosedlabs.com/peptides/peg-mgf/coas.

Where can researchers source PEG-MGF?

5 vendors with Disclosed Labs trust grades currently list PEG-MGF, including Peptidology, Skye Peptides, BioLongevity Labs. Compare live prices and lab-verified COAs at https://www.disclosedlabs.com/prices/peg-mgf.

Which prescribers offer PEG-MGF with a prescription?

3 prescribers in the Disclosed Labs directory work with PEG-MGF, each confirmed from their own website. PEG-MGF requires a prescription from a licensed provider. Browse them at https://www.disclosedlabs.com/prescribers?peptide=PEG-MGF.

How does PEG-MGF work?

The MGF E-peptide acts locally on muscle satellite (stem) cells, promoting their proliferation and delaying terminal differentiation, which expands the progenitor pool available for fusion into damaged myofibers. Receptor-blocking studies by Yang & Goldspink (2002) indicated that the E-peptide acts through a receptor distinct from the classical IGF-1R, although the exact receptor remains unconfirmed — this is one reason MGF is mechanistically separable from mature IGF-1 or IGF-1 LR3. Conjugation of polyethylene glycol to the peptide reduces renal clearance and proteolysis, extending plasma half-life from minutes (native MGF) to several hours.

What does the research say about PEG-MGF?

Yang and Goldspink (FEBS Lett 2002, PMID 12095637) established that the MGF E-peptide promotes myoblast proliferation and delays terminal differentiation through a receptor distinct from IGF-1R, separating MGF pharmacology from mature IGF-1. Kandalla et al. (Mech Ageing Dev 2011, PMID 21354439) showed the 24-aa MGF E-peptide activates human muscle progenitor cells and enhances their fusion potential even from older donors. Qin et al. (Mol Cell Biochem 2012, PMID 22875667) confirmed MGF drives satellite-cell proliferation while inhibiting differentiation by down-regulating MyoD and p21. Comprehensive reviews by Matheny, Nindl & Adamo (Endocrinology 2010, PMID 20130113) and Zabłocka, Goldspink et al. (Front Endocrinol 2012, PMID 23125840) summarize the evidence across muscle, cardiac and neural tissue and caution that MGF's receptor, in vivo pharmacokinetics, and safety profile remain incompletely characterized. No randomized controlled human trials of PEG-MGF have been published. MGF and IGF-1 analogs are prohibited at all times under the WADA Code.