MGF
Growth Factor Splice VariantresearchAlso known as: Mechano Growth Factor, IGF-1Ec, MGF peptide
A splice variant of IGF-1 produced locally in damaged muscle tissue that activates satellite cells and initiates muscle repair and growth following mechanical stress.
Overview
Mechano Growth Factor (MGF) is a splice variant of the IGF-1 gene (specifically the IGF-1Ec isoform in humans) that is expressed locally in muscle tissue in response to mechanical damage such as resistance training. Unlike systemic IGF-1, MGF is produced as a transient pulse in damaged muscle and acts primarily as an autocrine/paracrine signal to activate quiescent satellite cells — the muscle stem cells essential for repair and growth. The synthetic MGF peptide corresponds to the unique C-terminal E-domain of the IGF-1Ec splice variant, giving it distinct biological activity from standard IGF-1. MGF has a very short half-life (minutes) in its unmodified form, which led to the development of PEG-MGF for extended action. It is used in bodybuilding and performance communities for its targeted muscle repair and growth properties.
Mechanism of Action
MGF activates muscle repair through a unique pathway: (1) Binds to distinct receptors on satellite cells (not the standard IGF-1R), triggering their activation from quiescence; (2) Stimulates satellite cell proliferation without premature differentiation, building the pool of myogenic precursors; (3) Upregulates MyoD and other myogenic regulatory factors; (4) Creates a transient anabolic pulse that primes muscle for subsequent IGF-1-mediated differentiation and fusion; (5) Acts as a damage sensor — only expressed following mechanical stress or injury; (6) Promotes local angiogenesis to support tissue repair.
Molecular Formula
C121H200N42O39
Molecular Weight
2867.14 g/mol
Sequence
Tyr-Gln-Pro-Pro-Ser-Thr-Asn-Lys-Asn-Thr-Lys-Ser-Gln-Arg-Arg-Lys-Gly-Ser-Thr-Phe-Glu-Glu-Arg-Lys
Dosage Protocols
Dose Range
100mcg – 200mcg
Frequency
Post-workout (within 30 minutes)
Route
intramuscular (site-specific)
Cycle Length
4-5 weeks
Inject bilaterally into muscles trained. Very short half-life means it must be used immediately post-workout. Unmodified MGF is essentially a local-acting peptide.
Source: Community protocols
🧮 Personalized Dosage Calculator
💰 Estimated Pricing
Typical Supply
2mg vial
Last Updated
2026-02
Mechano Growth Factor. IGF-1 splice variant. Research: $30-60. Short half-life, site-specific injection. Bodybuilding use.
⚠️ Prices are estimates based on publicly available data and may vary significantly by vendor, location, and prescription status. This is not medical or financial advice.
Side Effects
| Effect | Severity |
|---|---|
| Injection site soreness | mild |
| Mild hypoglycemia | mild |
| Localized swelling | mild |
Pros & Cons
Specifically activates satellite cells — the key to real muscle fiber creation
Localized action reduces systemic side effects compared to IGF-1 analogs
Mimics the body's natural post-exercise repair signaling
Can be combined with IGF-1 LR3 in a sequential protocol for maximum effect
Extremely short half-life (minutes) severely limits practical effectiveness
Requires precise post-workout timing for any benefit
Limited human research data
PEG-MGF version generally preferred for practical use
Research Studies
🩸 Blood Work
No specific bloodwork requirements reported for this peptide. General health panels are always recommended before starting any peptide protocol.
Legal Status
Not FDA-approved. Available as a research chemical. Banned by WADA. Not explicitly scheduled but regulated as a research compound.
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