What Is PEG-MGF?
PEG-MGF is a pegylated (polyethylene-glycol-attached) version of Mechano Growth Factor (MGF) — the E-peptide of IGF-1Ec, a splice variant of insulin-like growth factor 1 that muscle produces locally in response to mechanical load and damage. Native MGF is released after resistance exercise or injury and is thought to help activate muscle satellite (stem) cells for repair; the PEGylation is added to extend its very short half-life so it can be used in research/injection protocols. It is marketed for muscle repair and growth, but it is a research peptide, not an approved drug or dietary supplement, and there are no human efficacy trials.
Evidence
The framing biology — MGF as a locally acting IGF-1 splice variant implicated in satellite-cell activation and muscle repair — is described in review literature on IGF-1Ec/MGF 1Reference 1Reviewhttps://pmc.ncbi.nlm.nih.gov/articles/PMC3795771/View study →. However, the picture is not simple: a peer-reviewed study reported that the synthetic MGF E-peptide (the COOH-terminus of unprocessed IGF-1) had no apparent effect on myoblasts or primary muscle stem cells in vitro, directly challenging the claimed satellite-cell mechanism 2Reference 2In vitrohttps://pubmed.ncbi.nlm.nih.gov/24253050/View study →. I found no human clinical trial of PEG-MGF for muscle growth, repair, or performance in this pass. The “muscle repair” marketing rests on the exercise-physiology of endogenous MGF plus animal/cell work, not on human outcome trials of the injected pegylated peptide, and even the underlying cell mechanism is contested 2Reference 2In vitrohttps://pubmed.ncbi.nlm.nih.gov/24253050/View study →. Human benefit is therefore unproven here.
Dosage & Safety
There is no established human dose for PEG-MGF; regimens circulating online are not from controlled human trials, and this page makes no dosing recommendation. It is not an approved drug or dietary supplement and, as a non-approved growth-factor peptide, is prohibited in sport. Human safety, long-term effects, drug interactions, and pregnancy/lactation safety are not established / not assessed in this pass. This entry is informational only and is not an endorsement of use.
References
- Insulin-Like Growth Factor I (IGF-1) Ec / Mechano Growth Factor — a splice variant of IGF-1 within the growth plate — review. https://pmc.ncbi.nlm.nih.gov/articles/PMC3795771/
- Mechano-growth factor peptide, the COOH terminus of unprocessed insulin-like growth factor 1, has no apparent effect on myoblasts or primary muscle stem cells — in vitro study. https://pubmed.ncbi.nlm.nih.gov/24253050/