Wellness and performance
Bones & muscles
Mechano growth factor
Also called MGF, PEG-MGF, IGF-1Ec
Mechano growth factor is a muscle IGF-1 splice variant sold as a research peptide. Evidence is mostly lab-based; it is not FDA-approved and is banned in sport.
- Reviewed by
- William Maish, MD MBA MPH, Clinical Product Lead
- Published
- October 5, 2026
- Last updated
- October 5, 2026
Key takeaway
Mechano growth factor (MGF) is a muscle-made splice variant of IGF-1, sold on the research-peptide market and often pegylated as PEG-MGF. Its strongest human evidence is observational. In a 2003 biopsy study, one bout of leg exercise raised MGF mRNA significantly in eight men aged 25 to 36 but not in seven men aged 70 to 82. There are no controlled human trials of MGF, and it is not FDA-approved and is banned in sport.
At a glance
| FDA status | Non-FDA-approved peptide sold as a research chemical / performance drug |
| What it is | Muscle-produced splice variant of IGF-1; a pegylated form (PEG-MGF) is also sold |
| Research | Laboratory and cell-based only; no human efficacy trials |
| Sport | Prohibited by WADA at all times |
| Evidence strength | Low research |
What is mechano growth factor?
Mechano growth factor (MGF, also called IGF-1Ec) is a variant of the IGF-1 gene produced in muscle that has been mechanically loaded or damaged. It has a unique tail region distinct from the IGF-1 that circulates in the blood. In the performance market it is sold as a muscle-repair peptide, frequently as a pegylated version (PEG-MGF) claimed to last longer. It is not an approved medicine.
How does it work?
MGF is proposed to act on muscle stem cells (satellite cells), activating them and helping them multiply and delay aging, which would support muscle repair and growth. This is attributed to its unique tail region, thought to work somewhat differently from the classic IGF-1 growth signal.
In human muscle-cell cultures, the MGF peptide enhanced satellite-cell activation and fusion, and laboratory versions promoted cell growth and migration. These are cell and laboratory findings. The pegylated form sold on the market is a modification that has not been characterized as a pharmaceutical. This describes the proposed mechanism, separate from proven outcomes in people.
Is it FDA-approved?
No. MGF and PEG-MGF are not approved by the FDA; they are research chemicals and performance-enhancing drugs with no approved compounding status. In sport, mechano growth factors are prohibited at all times under the WADA list.
What does the research show?
The evidence is preclinical. The table below summarizes the studies indexed on PubMed, from cell work to the strongest human finding, which is observational.
| Study | Design | Finding |
| A study1 | Human muscle-cell cultures | The MGF peptide enhanced satellite-cell activation and fusion, with age-dependent effects |
| A related laboratory study2 | Laboratory | Reported effects on cell growth and migration |
| Kandalla's cell study | Satellite cells from neonatal, young-adult, and old-adult donors | The MGF E peptide extended proliferative lifespan and delayed senescence3 in cells from neonatal and young-adult donors, but not from old-adult donors |
| A 2003 biopsy study4 | Observational, 8 men aged 25 to 36 and 7 aged 70 to 82 | One bout of leg exercise raised MGF mRNA significantly in the young men but not the older men; the study measured the body's own MGF and did not give MGF itself |
There are no controlled human trials of MGF or PEG-MGF for muscle or recovery, and the pegylated form specifically is uncharacterized. The marketed benefit is unproven in people.
More for bones & muscles
Sources: a human muscle-cell study of the MGF peptide (Kandalla et al., Mechanisms of Ageing and Development, 2011, DOI: 10.1016/j.mad.2011.02.0071) and a laboratory study of MGF and cell growth (Zhang et al., 2008, PubMed PMID 18837392), indexed on PubMed; and the WADA Prohibited List. This document is educational, is not medical advice or a health claim, and is not an offer to sell any product.