A name used for a modified growth-related peptide, often discussed for muscle growth and repair.
5-minute readFull profile reviewed July 31, 2026
Evidence is explained by question. Dosing references show their own check dates.
60-second overview
PEG-MGF at a glance
Why people look into it, what studies found, and what is still unknown.
Why people look into it
Whether making a growth-related fragment last longer changes tissue repair.
What studies found
No study giving PEG-MGF to people was located. Research on the body's own muscle signals or different, unmodified fragments does not establish PEG-MGF's effects.
What is still unclear
The exact product identity, human effects, interactions, and safety are unclear. Similar names do not make different molecules interchangeable.
About the evidence and review date
Educational information only. Evidence reviewed through July 31, 2026. Published studies, sponsor announcements, and trials without results are labeled separately. Evidence gaps apply to the specific finding beside them.
Research questions
Why people research it
Each label shows how much evidence supports that question.
Endogenous muscle-repair signalingTheory only
Human muscle progenitor-cell biologyAnimal or lab research
Cell migration and transplantation supportAnimal or lab research
Human muscle gain or hypertrophyNot demonstrated
Human injury recovery or tissue repairNot demonstrated
PEG-MGF pharmacokinetics and safetyNot demonstrated
What studies show
What the evidence supports
The research behind the answer
No administered human PEG-MGF evidence was identified. The closest human evidence consists of endogenous IGF-1Ec/MGF expression after exercise and laboratory exposure of human-derived muscle cells to defined non-PEG E-peptides.
See each finding and its sources (7)
Mechanistic rationale
PEG-MGF is a proposed PEGylated derivative of an MGF E-domain peptide, not the endogenous IGF-1Ec transcript or full pro-IGF-1Ec molecule.
The names MGF, IGF-1Ec, MGF E-peptide, and PEG-MGF are often blurred together even though they describe different biological or manufactured entities.
Commercial PEG-MGF descriptions often omit a validated sequence, PEG size, attachment site, positional purity, and analytical comparability standard.
Peer reviewedFull IGF-1Ec versus E-peptide functions
Peer reviewedIGF-1 splice variant and E-peptide distinction
Other human evidence
Human exercise studies show transient endogenous IGF-1Ec/MGF expression after muscle damage, but participants were not treated with MGF or PEG-MGF.
A body producing a transcript after exercise does not prove that injecting a manufactured analog reproduces the same biology.
PEGylation can change distribution, persistence, steric interactions, immunogenicity, and bioactivity; it cannot be assumed to preserve non-PEG MGF E-peptide findings.
A longer-lasting molecule is not automatically the same molecule with the same target, tissue exposure, or safety profile.
No validated PEG architecture or comparative pharmacology was identified for commercial PEG-MGF material.
Peer reviewedDefined non-PEG MGF E-peptide literature
PEGylation can change distribution, persistence, steric interactions, immunogenicity, and bioactivity; it cannot be assumed to preserve non-PEG MGF E-peptide findings.
Mechanistic evidence
No validated PEG architecture or comparative pharmacology was identified for commercial PEG-MGF material.
Missing reports do not establish safety. Findings apply to the product, route, amounts, population, comparison, and follow-up studied.
Side-effect frequency, study withdrawals, and gaps
How often side effects occurred
The available information does not reliably show how often particular side effects occur.
Evidence boundary
Under-detected or under-reported events must not be described as rare.
Why people stopped in studies
Relay has not verified which side effects led people to stop treatment in studies.
Evidence boundary
This is an evidence gap, not proof that discontinuations did not occur.
Warning information
Relay has not verified a compound-specific warning summary for this profile.
Evidence boundary
Not FDA approved; no exact administered human PEG-MGF study or validated pharmaceutical product standard identified The actual identity and pharmacology of PEG-MGF material, including peptide sequence, PEG size and attachment site, purity, tissue distribution, receptor interactions, persistence, immunogenicity, human safety, and whether any claimed muscle or recovery effect exists.
Emergency instructions
This profile does not contain verified, product-specific emergency instructions.
Evidence boundary
Relay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
Dosing references
Dosing & preparation
Each table labels its source and applies only to the named route, product, or study. An online example or community report is not an approved dose.
Route: Route unverified · No exact human administration route established in this review
Evidence gap · Route unverified
No verified regimen for this exact identity
PEG size, attachment, and peptide sequence can vary. Native MGF and IGF-1 research cannot supply a dose for an undefined PEG-MGF product.
What would fill this gap: A defined molecule and a direct human administration source.
Dosing review checked Oct 20, 2026. Additional sources are available below.
Formulation & handling · Route unverified
No route-specific preparation instructions were verified. A different route or product does not supply them.
Starting dose, maintenance, and trial targets explained
Starting dose: the amount used at the beginning of the named label schedule or trial.
Maintenance: the ongoing amount described by that product label.
Trial target: the amount assigned to a study group. Different groups may stop increasing at different targets.
Other source records, populations, and limits · all routes
No direct study for this identity
Related MGF expression study—not PEG-MGF administration
Amount in this source
A complete human regimen was not verified in this source record. See the dosing status above.
Frequency
No PEG-MGF exposure
Route
No administered PEG-MGF route; participants underwent exercise and muscle biopsy
Duration
Biopsies through 16 days after exercise
Population, study design, and limitations
The closest human record measured natural muscle-gene expression after exercise; participants were not given MGF or PEG-MGF.
Population: 10 healthy men for the biopsy component
Design: Serial human muscle biopsies after exercise-induced damage plus synthetic MGF E-peptide experiments in mouse myoblast-like cells
The synthetic peptide appeared only in a laboratory cell experiment and was not PEGylated.
This record cannot establish PEG-MGF identity, human exposure, efficacy, safety, or a preparation standard.
MGF is a name applied to the human IGF-1Ec splice variant and, separately, to synthetic peptides derived from its E-domain. Human exercise biopsies demonstrate transient endogenous IGF-1Ec/MGF expression after damage, while several laboratory groups reported migration, progenitor-cell, or transplantation effects from defined non-PEG E-peptides. Other investigators failed to reproduce key proliferative effects, and structure-function studies show that full pro-IGF-1Ec and isolated E-domain sequences are not functionally interchangeable. PEG-MGF adds another unvalidated layer: no exact PEG architecture, comparative pharmacology, administered human trial, or approved product standard was identified.
Why this matters
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Signals and targets
No validated PEG-MGF therapeutic receptorIGF-1 receptor - not required in several non-PEG cell assays
Proposed biological steps
Proposed MGF E-domain signaling
Proposed cell migration and progenitor-cell effects
PEGylation intended to alter persistence - not validated for this product
Possible IGF-1 receptor-independent cell signaling in selected assays
Research reference
How mature is the evidence?
A reference for the studies, populations, and routes behind this profile.
Research depthIndirect laboratory record
Research concerns endogenous MGF or non-PEG E-peptides; no administered human PEG-MGF study was found.
Why this matters
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
Evidence confidenceVery low for the marketed concept
Exact PEG identity, pharmacology, exposure, and human outcomes are unknown; related laboratory findings conflict.
Why this matters
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
Strongest evidenceHuman-derived cell studies of non-PEG MGF-related peptidesWhy this matters
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human evidenceNo administered human PEG-MGF evidenceWhy this matters
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Schedules studiedNo PEG-MGF exposure; Biopsies through 16 days after exercise
Amounts studiedWithheld: this record provides research context without a transferable amountWhy this matters
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-lifeNot established for this exact editorial recordWhy this matters
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Route evidenceThe closest human record measured natural muscle-gene expression after exercise; participants were not given MGF or PEG-MGF.Why this matters
Evidence can change by administration method. Findings from one route should not automatically be applied to another.
Evidence boundary: The synthetic peptide appeared only in a laboratory cell experiment and was not PEGylated. This record cannot establish PEG-MGF identity, human exposure, efficacy, safety, or a preparation standard. Amounts shown describe cited research exposure—not a dosage recommendation.
Studies
Study-by-study record
Study arms are reported for transparency. They describe what researchers did in a defined record and do not transfer across identities, routes, formulations, or populations.
Why this matters
A later trial phase can ask a more mature question, but it does not guarantee a positive result, regulatory approval, or relevance outside the studied population.
Laboratory studyPeer reviewed
Mechano-growth factor peptide, the COOH terminus of unprocessed insulin-like growth factor 1, has no apparent effect on myoblasts or primary muscle stem cells
Replication experiments in mouse myoblasts and primary human skeletal-muscle myoblasts
C2C12 cells and primary human skeletal-muscle cells
Outcomes measured
Proliferation
Differentiation
Primary muscle stem-cell activity
What was reported
The investigators did not reproduce previously reported proliferative or differentiation effects in the tested cell systems.
Study administration and important limits
Study administration: MGF-related peptide concentrations up to 500 ng/mL
Limitations: Negative cell results do not settle every possible MGF construct, but they demonstrate that the proposed biology is assay- and peptide-definition-dependent.
Laboratory studyPeer reviewed
Mechano Growth Factor E peptide, derived from an isoform of IGF-1, activates human muscle progenitor cells and induces an increase in their fusion potential at different ages
Laboratory exposure of primary human muscle progenitor cells from different ages
Human-derived neonatal, young-adult, and older-adult muscle cells
Outcomes measured
Proliferative lifespan
Senescence
Fusion
Reserve-cell fraction
What was reported
The synthetic E-peptide increased several progenitor-cell measures in younger cultures, with less consistent activity in older-adult cells.
Study administration and important limits
Study administration: Synthetic non-PEG 24-amino-acid MGF E-peptide
Limitations: In-vitro results with a defined non-PEG peptide do not establish whole-body muscle growth, injury recovery, dosing, pharmacokinetics, or PEG-MGF activity in people.
Laboratory studyPeer reviewed
Expression of IGF-1 isoforms after exercise-induced muscle damage in humans: characterization of the MGF E peptide actions in vitro
PhaseHuman exercise-expression and laboratory study
Population10 participants
DurationBiopsies through 16 days after exercise
Design and population
Serial human muscle biopsies after exercise-induced damage plus synthetic MGF E-peptide experiments in mouse myoblast-like cells
10 healthy men for the biopsy component
Outcomes measured
IGF-1 isoform expression
MGF expression
Cell proliferation signaling
What was reported
Endogenous MGF/IGF-1Ec expression increased transiently after muscle damage. A synthetic non-PEG E-peptide showed laboratory effects distinct from mature IGF-1.
Study administration and important limits
Study administration: Exercise-induced muscle damage; synthetic non-PEG MGF E-peptide was used only in laboratory cells
Limitations: The human participants were not given MGF or PEG-MGF. Endogenous transcript expression and cell-culture peptide effects do not establish an injectable PEGylated treatment.
Animal studyPeer reviewed
A synthetic mechano growth factor E Peptide enhances myogenic precursor cell transplantation success
PubMed and ClinicalTrials.gov searches for PEG-MGF
Population not stated.
Outcomes measured
Direct PEG-MGF human evidence
What was reported
Relay did not identify an administered human PEG-MGF trial or an exact registered clinical-development program.
Study administration and important limits
Study administration: Not stated in the current record.
Limitations: Search audits cannot prove that no unpublished or unregistered experiment exists, but they prevent non-PEG and endogenous findings from being mislabeled as direct PEG-MGF evidence.
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Mechano-growth factor peptide, the COOH terminus of unprocessed insulin-like growth factor 1, has no apparent effect on myoblasts or primary muscle stem cells
2014-01-15 · PMID 24253050 · DOI 10.1152/ajpendo.00408.2013
Mechano Growth Factor E peptide, derived from an isoform of IGF-1, activates human muscle progenitor cells and induces an increase in their fusion potential at different ages
2011-04-01 · PMID 21354439 · DOI 10.1016/j.mad.2011.02.007