MGF (Mechano Growth Factor)
Muscle Building, Repair and Recovery
In short
- A splice variant of IGF-1 (IGF-1Ec) produced in muscle in response to mechanical loading and damage.
- The endogenous biology is genuine and well published — MGF expression rises after resistance exercise and injury.
- The research-market product is the synthetic E-domain peptide, which is not the same as the full splice variant.
- Extremely short half-life — minutes — because the unmodified peptide is rapidly degraded in serum.
- No human trial of administered MGF exists. Prohibited at all times in sport.
Structure
A 24-amino-acid IGF-1 splice variant peptide. PubChem has no entry under this research-market name, and peptides and proteins of this size are represented by sequence rather than a small-molecule structure diagram.
How it works
Alternative splicing of the IGF-1 gene produces IGF-1Ec, known as mechano growth factor, whose distinguishing feature is a unique C-terminal E-domain. Expression is upregulated by mechanical loading and muscle damage.
The E-domain peptide is reported to act independently of the IGF-1 receptor, stimulating satellite cell proliferation and migration — the muscle stem cells responsible for repair and for adding myonuclei during hypertrophy.
The research-market product is a synthetic version of that E-domain sequence alone. Whether an isolated 24-amino-acid fragment reproduces the biology of the full splice variant in vivo is unestablished.
What the research shows
Endogenous MGF expression after resistance exercise and injury is well documented in humans — that part is solid muscle physiology.
Rodent and cell-culture work with the synthetic peptide reports satellite cell activation and effects on muscle repair.
No human study of administered MGF has been published. Claims about localised muscle growth from injection are unsupported.
Dosing in the literature
Figures below are quoted from published studies, with the species or population they were measured in. They are records of what was studied, not recommendations.
| Studied in | Amount | Route | Source |
|---|---|---|---|
| Rodent and cell culture — satellite cell and muscle repair studies | Varies widely by model; see source | — | PubMed |
Commonly reported ranges
These are amounts people report using. They are not from any study, have not been evaluated for safety, and are reproduced here only because they circulate widely and are better seen alongside the evidence than instead of it.
| Reported by | Amount | Route |
|---|---|---|
| Commonly reported, post-training | 200–400 µg per site | subcutaneous or intramuscular |
No published human pharmacokinetic study establishes a dose, interval, or duration for this compound. Community figures below have no trial behind them and are reports of practice, not evidence. The minutes-long serum half-life of the unmodified peptide is the practical problem: whatever is injected is largely degraded before it can distribute. This is the specific reason the PEGylated version exists.
Handling and storage
Supplied as a lyophilised powder requiring reconstitution with bacteriostatic water. The powder is comparatively stable; once reconstituted it is refrigerated and used within weeks. Track the date you reconstitute each vial — the Inventory section does this, and it is the difference between knowing a vial is three weeks old and guessing.
Subcutaneous or intramuscular injection near the trained muscle is the community pattern, on a localised-action rationale. Post-training timing is commonly described, mirroring when endogenous expression rises.
MGF is reported to be particularly unstable in solution, so reconstituted material degrades faster than most peptides here.
Side effects
No human safety data exists.
Community reports centre on injection-site reactions and post-injection soreness.
The mechanistic concern is shared with the IGF-1 family: a compound promoting cell proliferation carries theoretical proliferative risk. MGF acts on satellite cells rather than systemically through the IGF-1 receptor, which may narrow that concern, but it has not been characterised in humans either way.
Combinations
Commonly combined with IGF-1 analogues or GH secretagogues, which compounds growth-factor signalling from several directions with no interaction data.
The endogenous biology says MGF acts downstream of mechanical loading, which is to say training is the input the pathway was designed around.
Research status
The IGF-1 splice variant literature is genuine, largely from Geoffrey Goldspink's group and successors, covering exercise-induced expression and satellite cell biology.
No clinical trial of the synthetic peptide has been registered or completed.
Legal status
Not approved in any jurisdiction. Sold for research use only.
WADA status
PROHIBITED AT ALL TIMES under WADA class S2 — growth hormone secretagogues, their releasing factors and mimetics are explicitly named. Any tested athlete should treat this as an anti-doping violation.
Conclusion
MGF is real muscle physiology attached to a research-market product that has never been tested in a human and degrades in minutes.
The endogenous pathway responds to mechanical loading. The most reliable way to raise MGF expression remains training, which is free and evidenced.
Sources
Track your own MGF (Mechano Growth Factor) protocol
Peppers logs your doses, models your levels from this half-life, tracks your vials and tells you when you will run out. Free on iPhone.
Reference and educational information only. Not medical advice. Nothing here diagnoses, treats, or prescribes, and nothing here is a recommendation to use any compound. The compounds described are research chemicals and are not approved for human consumption. Legal and anti-doping status change — the review date above is when these claims were last checked. Talk to a qualified clinician about anything you intend to take.