What it is
PEG-MGF is a lab-made peptide with a chemical chain attached. The peptide part is 24 amino acids long. It copies the end piece of MGF, short for mechano growth factor. MGF is a version of IGF-1 that muscle makes after hard use or injury. The body makes it by splicing the IGF-1 gene a different way. The chain attached is PEG, short for polyethylene glycol. PEG is added to slow how fast the peptide breaks down. The plain peptide breaks down in minutes. MGF is related to IGF-1. See the IGF-1 LR3 entry for that compound. Other names: Pegylated Mechano Growth Factor, PEG IGF-1Ec, MGF E-peptide.
What researchers study it for
- Muscle stem cells, called satellite cells
- Muscle cell transplants in mice
- How it signals without the IGF-1 receptor
- Muscle cells from young and old donors
- Inflammation after muscle injury in mice
What the studies found
1. It made muscle cells multiply instead of mature.
A 2002 study compared the MGF end piece with regular IGF-1 in young muscle cells. The MGF piece made the cells divide more. It held back the step where cells mature into muscle fiber. Regular IGF-1 did the opposite. Blocking the IGF-1 receptor stopped regular IGF-1 but not the MGF piece. Lab cells only.
2. It helped transplanted human muscle cells take hold in mice.
A 2007 study tested the 24 amino acid MGF piece with human muscle precursor cells. These cells are studied as a treatment for muscular dystrophy. Mice given the peptide kept more of the transplanted cells. In the lab, the peptide made the cells divide more and mature later. Cell and mouse data.
3. Muscle stem cells from young donors responded. Cells from an old donor did not.
A 2011 study added the MGF piece to human muscle stem cells from donors of different ages. Cells from babies and young adults kept dividing longer before they wore out. Cells from a 73-year-old donor did not show this. In every age group, the pool of backup stem cells shrank. Lab cells only.
4. It worked on heart cells without the IGF-1 receptor.
A 2009 study looked at rat hearts after a heart attack and at rat heart cells in a dish. MGF levels rose in the damaged heart weeks after the attack. In the dish, blocking the IGF-1 receptor did not stop the MGF piece. It turned on a signal called ERK1/2 but not a second signal called Akt. The receptor it uses is still not known. Animal and lab cell data.
5. Too much MGF slowed the end of inflammation after muscle injury.
A 2018 study injured mouse leg muscle and tracked MGF. Immune cells called macrophages made most of the MGF after injury. Mice made to produce extra MGF kept inflammation going longer. Muscle repair did not improve. Mouse data only.
How much research exists
A small number of lab cell and animal studies. Almost all used the plain peptide, not the PEG form. No study has tested PEG-MGF itself. No human trial has been published.
Facts
- Formula: C121H199N41O40 (peptide part only, without PEG)
- Weight: about 2868 g/mol for the peptide part. The PEG form has no single weight.
- CAS number: none found
- Sequence: YQPPSTNKNTKSQRRKGSTFEERK (peptide part)
- Time in the blood: never measured for PEG-MGF. The plain peptide breaks down in minutes.
- Storage: powder in the freezer, away from light and moisture.
Legal status
Not approved by the FDA or any other agency for human use. Banned in sports by WADA under section S2, which names mechano growth factors.
For research use only. Not for human use. Nothing here is medical advice.