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MGF: quick citable summary
MGF is listed by PeptaHub as a muscle & growth peptide with a research only legal-status classification. The page summarizes mechanism, research context, common routes, safety notes, and references for writers and AI answer engines.
PeptaHub. “MGF: Mechanism, Research Context, Safety.” peptahub.com, 2026. https://peptahub.com/peptides/mgf. Licensed CC BY 4.0.
License: Creative Commons Attribution 4.0 International. Link back to https://peptahub.com/peptides/mgf.
What is MGF?
MGF (Mechano Growth Factor / IGF-1Ec) is a splice variant of IGF-1 produced locally in muscle after mechanical loading or injury. It specifically activates quiescent satellite cells for muscle repair and hypertrophy, working through a unique E-peptide that does not bind the IGF-1 receptor.
Overview
MGF (Mechano Growth Factor), also designated IGF-1Ec, is a splice variant of insulin-like growth factor 1 (IGF-1) produced locally in muscle tissue in response to mechanical loading and injury. Unlike systemic IGF-1, MGF is transiently expressed at the site of damage and specifically activates quiescent muscle satellite cells — the resident stem cells responsible for muscle repair and hypertrophy. It is used in research and by athletes interested in accelerating muscle recovery.
Mechanism of action
MGF arises from alternative splicing of the IGF-1 gene: a 49-base-pair insert in exon 5 causes a reading frame shift, producing a unique carboxy-terminal E-domain peptide (the MGF E-peptide) that does not bind the IGF-1 receptor and signals through distinct, incompletely characterized pathways. When muscle fibers are subjected to mechanical strain or damage, the IGF-1 gene is preferentially spliced toward the MGF (IGF-1Ec/Eb) isoform. The resulting MGF E-peptide activates quiescent satellite cells — inducing proliferation without differentiation — expanding the progenitor pool available for repair. Mature IGF-1 (primarily IGF-1Ea splice variant) then drives satellite cell differentiation, fusion into existing fibers, and net fiber hypertrophy. This two-phase sequence (MGF: proliferate; IGF-1Ea: differentiate) explains why exogenous MGF, timed post-exercise or post-injury, may amplify the hypertrophic response. Pegylation is used commercially to slow clearance of the native peptide, but no published pharmacokinetic study of PEG-MGF quantifies the result.
Reported study ranges
| Purpose | Route | Reported range | Frequency | Notes |
|---|---|---|---|---|
| Muscle recovery / satellite cell activation | intramuscular | 200–400 mcg | 2-3x per week post-workout | Community-reported range with no clinical trial behind it. No human study of MGF has been published, so neither the dose nor the timing is trial-derived. |
| PEG-MGF muscle recovery | subcutaneous | 200–400 mcg | 2-3x per week | PEG-MGF extends half-life significantly, allowing less frequent dosing. Subcutaneous or intramuscular administration. |
Reported ranges are for research context only. Consult a qualified healthcare professional before using any peptide.
Convert MGF research-range units
Need to convert mg to mcg, dose volume, or U-100 syringe units? The MGF dose calculator is preloaded with these ranges, or use the general dose unit converter.
Research summary
The most directly relevant study used primary human muscle cell cultures from donors of different ages, and its result cuts against the way MGF is marketed: the MGF 24-amino-acid E peptide increased proliferative lifespan and delayed senescence in satellite cells from neonatal and young adult muscle, but not in cells from old adult muscle (Kandalla, Mech Ageing Dev 2011). In porcine satellite cells, MGF promoted proliferation and inhibited differentiation by downregulating myogenic transcription factors (Qin, Mol Cell Biochem 2012). A 2017 Molecular Brain study reported that MGF promotes neurogenesis in the aging mouse brain. No human clinical trial of MGF has been completed. No published study is cited here for a specific effective concentration or for post-injury injection in rodents.[1][2][3][4][5]
Evidence grading
Each claimed benefit is graded by the strength of available evidence. Grades reflect study quality, not effect size.
Strong = multiple RCTs · Moderate = limited trials or observational · Preliminary = animal or in vitro only · Insufficient = anecdotal or no published data
Side effects
Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.
Common stacks
Peptides commonly paired with MGF for synergistic effects.
Legal status
MGF and PEG-MGF are unscheduled research chemicals with no FDA-approved medical use. Not approved for human administration. Sold legally as research chemicals in many jurisdictions, though the same FDA enforcement actions affecting other peptides have affected MGF availability in the US. Prohibited by WADA in competitive sport.
Sourcing & access
Research compound
MGF is classified as a research compound. Regulatory status varies by jurisdiction. Always verify current legal status and source from vendors providing third-party certificates of analysis (COA).
Frequently asked questions
MGF (Mechano Growth Factor), designated IGF-1Ec, is an IGF-1 splice variant produced locally in muscle tissue in response to mechanical strain or injury. Unlike systemic IGF-1, it specifically activates quiescent satellite cells (muscle stem cells) for repair and growth.
When muscle is strained or damaged, the IGF-1 gene is spliced toward the MGF isoform. The MGF E-peptide activates satellite cells, inducing proliferation without differentiation. Mature IGF-1 then drives differentiation and fiber fusion. This two-phase sequence (MGF: proliferate, IGF-1: differentiate) enables the hypertrophic response.
Side effects include injection site pain or swelling, theoretical hypoglycemia risk (shared with the IGF-1 family), local tissue growth with repeated IM injection, headache, and fatigue. No human clinical trials have been completed and long-term effects are unknown.
PEG-MGF is the pegylated form, and pegylation is used to slow clearance. No published pharmacokinetic study of either native MGF or PEG-MGF quantifies the half-life of either, so the specific figures circulated in community sources are unsourced. The difference in dosing frequency between the two reflects community convention rather than measured pharmacokinetics.
Research references
- Minireview: Mechano-growth factor: a putative product of IGF-I gene expression involved in tissue repair and regenerationReview
- Mechano Growth Factor E peptide (MGF-E), derived from an isoform of IGF-1, activates human muscle progenitor cells and induces an increase in their fusion potential at different agesPubMed
- Mechano growth factor (MGF) promotes proliferation and inhibits differentiation of porcine satellite cells (PSCs) by down-regulation of key myogenic transcriptional factorsPubMed
- Mechano growth factor, a splice variant of IGF-1, promotes neurogenesis in the aging mouse brainPubMed
- Impairment of IGF-I gene splicing and MGF expression associated with muscle wastingPubMed