MGF
Mechano Growth Factor - the locally produced IGF-1 splice variant that activates muscle satellite cells after mechanical stress, driving muscle repair and hypertrophy.
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Compound Profile
MGF
Key Data
Research reference only
Research Focus
Preclinical data
⚠ Research & Educational Use Only. MGF is a research chemical documented here for scientific education. All information references peer-reviewed literature and preclinical/clinical study data. Not for human consumption. Not medical advice. Consult a licensed researcher or healthcare professional before any laboratory use.
- Activates quiescent muscle satellite cells - the stem-cell pool responsible for muscle repair and growth
- Promotes proliferation of myoblasts following mechanical damage or resistance exercise
- Works complementarily with IGF-1 LR3: MGF initiates satellite cell activation, systemic IGF-1 drives differentiation
- MGF is not FDA-approved for human use. It is a research chemical for scientific study only.
Research At a Glance
- Activates quiescent muscle satellite cells - the stem-cell pool responsible for muscle repair and growth
- Promotes proliferation of myoblasts following mechanical damage or resistance exercise
- Works complementarily with IGF-1 LR3: MGF initiates satellite cell activation, systemic IGF-1 drives differentiation
- Stimulates protein synthesis and upregulates mTOR signalling in muscle tissue
In Plain English
Simple summaryMGF (Mechano Growth Factor) is a splice variant of IGF-1 that muscle tissue produces locally in response to mechanical load -- exercise, stretching, and injury. When muscle fibers are stressed or damaged, a specific splicing event produces MGF rather than systemic IGF-1. MGF's job is local: it activates muscle satellite cells (the stem cells that repair and grow muscle) in the immediate vicinity of the damage. This is the repair signal that makes muscle grow stronger after you stress it. The E-domain peptide at the C-terminus of MGF is the part researchers focus on most -- it's the region that differs from systemic IGF-1 and is responsible for the satellite cell activation. Because of this local-acting mechano-responsive nature, MGF has been studied as a potential therapeutic for muscle wasting conditions where the normal repair signal is absent or insufficient.
- Activates quiescent muscle satellite cells - the stem-cell pool responsible for muscle repair and growth
- Promotes proliferation of myoblasts following mechanical damage or resistance exercise
- Works complementarily with IGF-1 LR3: MGF initiates satellite cell activation, systemic IGF-1 drives differentiation
The full scientific detail, mechanisms, citations, and dosing data, follows below.
What is MGF?
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MGF (Mechano Growth Factor) is a splice variant of insulin-like growth factor-1 (IGF-1) that is produced locally in muscle tissue in response to mechanical stress, damage, or exercise. Unlike systemic IGF-1 - which is primarily produced in the liver and circulates throughout the body - MGF is generated within the muscle itself via alternative mRNA splicing of the IGF-1 gene.
The discovery of MGF came from research into why muscles hypertrophy in response to exercise - a puzzle that systemic IGF-1 alone could not fully explain. The key finding was that a unique E-peptide extension at the C-terminal of the MGF isoform activates satellite cells - the quiescent muscle stem cells that reside beneath the basal lamina of muscle fibres. These satellite cells are essential for muscle repair and hypertrophy: they fuse with damaged fibres to repair them, and can form entirely new fibres following sufficient stimulus.
The working model of muscle hypertrophy now positions MGF as the first responder after mechanical damage: the local production of MGF activates satellite cells and drives their proliferation. Subsequently, systemic IGF-1 (or the IGF-1 Ec/MGF precursor) drives differentiation of these proliferating satellite cells into mature muscle fibres. This two-phase model explains why both local and systemic IGF-1 are needed for complete hypertrophy - and why timing between MGF and IGF-1 LR3 is important in research protocols.
A critical limitation of native MGF is its extremely short half-life in serum - degradation occurs within minutes due to the unprotected E-peptide. This necessitates intramuscular injection directly into target tissue immediately after exercise, before the mechanical signal has dissipated. This practical limitation led to the development of PEG-MGF (pegylated MGF), which has a dramatically extended half-life and can be administered subcutaneously.
Beyond muscle, MGF receptor expression has been documented in the CNS, cardiac tissue, and bone - suggesting broader roles in tissue maintenance. Research in myocardial infarction models showed MGF administration could reduce infarct size and improve cardiac recovery, pointing to potential applications in cardiac repair research.
By the Numbers
Key Research Benefits
Documented effects observed in preclinical and clinical studies on MGF. See all Muscle & Performance peptides for comparison.
Common Stacks
MGF is frequently combined with the following peptides for synergistic effects. Click any peptide to compare profiles before deciding.
BPC-157 helps manage the GI side effects associated with triple agonist therapy during dose escalation.
Retatrutide is the next-generation dual/triple agonist successor - research often compares them rather than combines them.
Side Effects & Risks
Adverse effects reported in the research literature. All data sourced from preclinical and clinical study reports. View all peptides' side effects →
Dosing Data from the Literature
Doses referenced below are sourced from published preclinical and clinical studies. Use the peptide dose calculator to convert these values to injection volume.
MGF research typically uses 100-200 mcg per injection, administered intramuscularly into the target muscle group immediately post-workout (within 30-60 minutes of exercise stimulus).
Standard research dose: 100-200 mcg IM per site Timing: immediately post-mechanical stimulus (exercise) Frequency: 2-4 times per week, correlated with training sessions Often followed by: IGF-1 LR3 administered 1-2 hours later to drive differentiation of activated satellite cells
Administration in Research Settings
Standard reconstitution and administration methodology for laboratory research use.
Reconstitute with bacteriostatic water. Due to its extremely short half-life in serum, MGF must be injected intramuscularly (not subcutaneously) directly into the target muscle group immediately after mechanical stimulation (exercise). Subcutaneous injection results in near-complete degradation before reaching target tissue.
PEG-MGF is the pegylated alternative with dramatically extended half-life and can be administered subcutaneously.
What the research doesn't show
MGF's very short plasma half-life (minutes) means that injected MGF is largely degraded before it can reach muscle tissue at meaningful concentrations. This is why PEG-MGF was developed. Research on plain MGF as an injectable intervention needs to account for this delivery problem, and many cited 'MGF results' in community forums conflate MGF with PEG-MGF.
Medical Expert Videos
Physicians, researchers, and pharmacologists explain MGF, covering mechanisms of action, clinical context, and study findings.
Videos sourced from YouTube search. KnowYourPeptide does not endorse any individual creator. For research education only.
The Bottom Line
MGF has a growing body of preclinical evidence and a well-characterised safety profile in research settings. The most-studied application is: activates quiescent muscle satellite cells - the stem-cell pool responsible for muscle repair and growth.
The most commonly reported side effect in research subjects is extremely short serum half-life - degraded within minutes, necessitating post-workout timing. It is a research chemical, not approved for human use.
Frequently Asked Questions
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Quick Reference
How It Compares
PEG-MGF (pegylated MGF) is the stabilized version with a much longer half-life, making it more practical for research protocols. Systemic IGF-1 LR3 bypasses the local mechano-responsive splicing step but activates similar downstream signaling globally rather than locally. MGF is the natural local signal; IGF-1 LR3 is the systemic amplifier.
Compare MGF side-by-sideResearch Use Only
This information is for educational research purposes only. This is not medical advice. Consult a qualified healthcare professional.