MGF
Also known as: Mechano Growth Factor, IGF-1Ec, IGF-1Eb (rodent), PEG-MGF
Overview
Mechano Growth Factor (MGF) is a splice variant of IGF-1 (the IGF-1Ec isoform in humans, IGF-1Eb in rodents) produced in skeletal muscle in response to mechanical load, exercise, and muscle damage. Unlike systemic IGF-1 which drives myoblast differentiation, MGF specifically activates satellite cell proliferation through a receptor distinct from IGF-1R. It expands the pool of muscle stem cells before differentiation signals arrive, representing the first response to mechanical injury. Pegylated MGF (PEG-MGF) is a stabilized research form with extended half-life.
Mechanism of Action
MGF's C-terminal E-domain peptide (MGF-Ct24E) acts through a receptor that is distinct from IGF-1R — it does not displace radiolabeled IGF-1 (IC50 >10,000 nM) and does not activate Akt via IGF-1R pathway at physiological concentrations. Instead, it keeps satellite cells in a proliferative state (expanding Pax7+ pool) without driving premature differentiation. In mechanically loaded myoblasts, endogenous MGF mRNA peaks at 2 hours post-stretch (3.2-4.4× increase), preceding systemic IGF-1 induction (peak 6-8 hours). Sequential use (MGF first, then IGF-1 LR3) produces the largest myotube formation.
Potential Benefits
- Satellite cell pool expansion for muscle repair and growth
- Mechanosensitive response mimicry enabling ex vivo satellite cell activation
- Enhanced muscle regeneration after injury (18-22% higher tetanic force recovery)
- Synergistic combination with IGF-1 LR3 for complete hypertrophy program
- More satellite cells available during recovery (34-42% greater centronucleation at day 7)
- Heart muscle and neural tissue protective effects in some studies
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Beginner | 200-250 mcg daily — assess tolerance for 1-2 weeks |
| Intermediate | 300-500 mcg daily |
| Advanced | 500-1000 mcg daily, split AM/PM |
| Cycle Duration | 4-8 weeks |
Research-community dosing based on published protocols. Consult a qualified clinician before use.
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Subcutaneous Injection High — systemic distribution
Most common administration route for research peptides. Inject into abdominal fat, thigh, or upper arm. Rotate sites. standard research dose.
Intramuscular Injection High — with slightly faster onset than SC
Alternative route when deeper delivery or faster absorption is desired. Less commonly used than SC for most research peptides.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving MGF:
Muscle Repair Stack
Full IGF-1 variant stack for muscle growth. MGF for immediate post-workout satellite cell activation (short window), PEG-MGF for extended signaling, IGF-1 LR3 for sustained anabolic drive.
Post-Training Recovery Stack
Rapid post-workout recovery. MGF immediately activates satellite cells, BPC-157 and TB-500 provide comprehensive tissue repair for muscle, tendon, and connective tissue.
Explore our complete Peptide Stacking Guide for more combinations and safety considerations.
Reconstitution
| Storage | Refrigerate at 2-8°C after reconstitution. Do not freeze reconstituted solution. |
|---|
Typical vial sizes: 5 mg. Add bac water slowly down the side of the vial, swirl gently — do not shake. Use insulin syringe for precise dosing.
Need exact syringe measurements?
Amino Acid Sequence
E-domain peptide MGF-Ct24E: Tyr-Gln-Pro-Pro-Ser-Thr-Asn-Lys-Asn-Thr-Lys-Ser-Gln-Arg-Arg-Lys-Gly-Ser-Thr-Phe-Glu-Glu-Arg-Lys
Side Effects & Safety
- Limited human safety data
- Possible insulin-like hypoglycemic effects at high doses
- PEG addition may reduce immunogenicity but add theoretical toxicity concerns
- Injection site reactions
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
Active Malignancy
Pregnancy / Lactation
Bleeding Disorders
Active Skin Infection at Injection Site
Pharmacokinetics
| Half-Life | ~5-7 minutes (native); hours with PEGylation |
|---|---|
| Storage | Store lyophilized peptide at -20°C (long-term) or 2-8°C (short-term, under 30 days). Reconstituted: refrigerate at 2-8°C and use within 28-30 days. Protect from light. Do not freeze reconstituted solution. |
Synergistic Compounds
The following compounds have been studied alongside MGF for potential complementary or synergistic effects:
Learn More
References & Further Reading
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