The name describes a polyethylene glycol conjugate of the peptide called mechano growth factor — a 24-residue chain corresponding to the C-terminal E domain of the IGF-1Ec splice variant of the insulin-like growth factor 1 gene . Beyond that, the name specifies very little: it does not state the molecular weight of the polymer, whether it is linear or branched, what chemistry attaches it, or which residue it attaches to. Those parameters define the substance, and none of them is fixed by the name.

PEG-MGF Research, Specifications & Scientific Information

PEG-MGF is a polyethylene glycol conjugate of the 24-residue peptide known as mechano growth factor. No public substance register carries a record for the conjugate, and no study of it in humans, animals or cell culture has been identified in the peer-reviewed literature. It is not approved by the FDA for any indication.

By Elegance Peptides Editorial TeamPublished September 22, 2026Updated September 22, 2026

Category: IGF and growth-factor peptides

Introduction

This is a short page, and the shortness is the substance of it.

PEG-MGF is a polyethylene glycol conjugate of the peptide called mechano growth factor. The peptide moiety has a register record, a defined sequence and a real if contested scientific literature. The conjugate has none of those things. No public substance register carries it. No clinical trial has studied it. No animal study has studied it. No cell-culture characterisation of it has been identified in the peer-reviewed literature — not a binding assay, not a pharmacokinetic measurement, not a stability comparison against the unconjugated peptide.

A 2026 narrative review in Frontiers in Endocrinology sorted the peptides that circulate around the growth hormone and insulin-like growth factor axis into evidence tiers, running from regulatory-grade randomised trial data at one end to a complete absence of human studies at the other, and placed pegylated mechano growth factor in that last tier ^[5].

This page does not pad that absence with evidence about a different compound. What follows is what can be said, with the boundaries marked.

What Is PEG-MGF?

PEG-MGF is a name for a chemical operation applied to a known peptide, and it is worth separating those two halves.

The peptide half is defined. Mechano growth factor is a 24-residue chain, YQPPSTNKNTKSQRRKGSTFEERK, corresponding to the C-terminal portion of the E domain of IGF-1Ec — an alternatively spliced transcript of the insulin-like growth factor 1 gene, first cloned in 1996 from stretched rabbit tissue ^[1]. The FDA/NCATS Global Substance Registration System carries it under UNII Q86M4KXC2P with a calculated average mass of 2868.17 g/mol. The MGF entry in this library sets out its literature, including the 2014 multi-laboratory failure to reproduce its central in vitro findings ^[3].

The conjugate half is not defined. Polyethylene glycol conjugation is a family of chemistries, not a single operation. A conjugate is specified by the molecular weight of the polymer, whether it is linear or branched, the linker chemistry, and the residue the polymer is attached to. None of those is stated by the name PEG-MGF, and no register, monograph or published characterisation supplies them. Two preparations sold under that name are not necessarily the same substance.

It is not an approved medicine anywhere, and no product containing it is known to have been submitted for approval.

PEG-MGF Specifications

Compound name: PEG-MGF
Full chemical name: Not publicly characterised
Aliases: pegylated mechano growth factor, PEG mechano growth factor, pegylated IGF-1Ec peptide
Development code: Not publicly characterised
CAS number: Not publicly characterised
PubChem CID: Not publicly characterised
UNII: Not publicly characterised
Compound type: Polyethylene glycol conjugate of a synthetic peptide; conjugate not defined by any public register
Peptide family: Insulin-like growth factor family, E-domain peptides (peptide moiety)
Amino acid sequence: Not publicly characterised
Sequence length: Not publicly characterised
Molecular formula: Not publicly characterised
Molecular weight: Not publicly characterised
Primary target: Not established. No receptor has been identified for the peptide moiety, and no binding study of the conjugate has been published.
Secondary targets: Not publicly characterised
Receptor family: Not publicly characterised
Agonist / antagonist status: Not established

No public substance register carries a record for PEG-MGF, and every identifier field on this page is therefore blank rather than estimated. That is not an omission; it is the finding. The name describes a polyethylene glycol conjugate of the peptide named mechano growth factor, which the FDA/NCATS Global Substance Registration System does carry, as a 24-residue chain under UNII Q86M4KXC2P with a calculated average mass of 2868.17 g/mol. A conjugate, however, is not specified by naming its peptide: the molecular weight and branching of the polyethylene glycol, the chemistry used to attach it, and the residue it is attached to all change the substance, and none of those parameters is fixed by the name PEG-MGF. Two preparations sold under that name need not be the same compound, and no register, monograph or peer-reviewed characterisation establishes what either of them is. A molecular weight cannot be stated for the same reason: it is the sum of a known peptide and an unspecified polymer. The certificate of analysis supplied with a laboratory order is the only record of what a given lot contains.

Values that a public register does not carry are shown as not publicly characterised rather than estimated. Identifiers are reference values; the certificate of analysis supplied with a laboratory order is the record for a given lot.

How Does PEG-MGF Work?

Not established — and the uncertainty is two layers deep rather than one.

The peptide's mechanism is unresolved. The original reports on the unconjugated peptide concluded that its in vitro activity was not mediated by the type 1 IGF receptor and inferred a different receptor. No such receptor has ever been identified. A 2010 review in Endocrinology went further and recorded that no peptide product of the insulin-like growth factor 1 gene corresponding to this sequence had been identified in or isolated from cultured cells, conditioned medium, animal tissues or biological fluids ^[2]. In 2014, investigators at two pharmaceutical companies tested the peptide's reported effects on proliferation, differentiation and ERK activation across four cell systems and found none, while positive controls responded normally ^[3].

The conjugate's contribution is unmeasured. The rationale usually offered for attaching polyethylene glycol is half-life extension, and that is a real and well-characterised strategy: conjugation increases hydrodynamic size, which slows renal clearance and proteolysis, and it is one of the standard approaches to extending the circulating lifetime of peptides and proteins ^[4]. But the magnitude of that effect is a property of a specific conjugate, established by measurement, and conjugation frequently costs potency where the polymer sits near the binding surface. For this compound there is no such measurement — no half-life, no clearance figure, no comparison of activity before and after conjugation.

Stating a mechanism here would require assuming both that the peptide has one and that the conjugate preserves it. Neither assumption is supported.

What Is PEG-MGF Being Researched For?

Nothing that this page can verify.

A search of the peer-reviewed literature and of public trial registers identifies no study in which this conjugate was administered, applied or characterised. The only peer-reviewed source located that names the compound at all is the 2026 review cited above, and it names it in order to classify it as lacking human evidence ^[5].

Two neighbouring literatures exist and should not be mistaken for this one:

The unconjugated peptide. A contested in vitro record running from 2002 to the present, together with rodent and human studies of the endogenous splice transcript rather than of an administered peptide. That record is set out in the MGF entry and belongs there.
Polyethylene glycol conjugation as a technique. A large and mature literature about half-life extension for peptides and proteins in general ^[4]. It establishes what the technique does on average across many molecules. It establishes nothing about any particular untested conjugate.

Neither of those is research into PEG-MGF, and combining them does not produce research into PEG-MGF.

Current Research Status

Regulatory status (United States): Not approved. No product containing this conjugate has been approved by the U.S. Food and Drug Administration for any indication, and none is known to have been submitted for approval.
Investigational status: No clinical trial, no animal study and no in vitro characterisation of this conjugate has been identified in public trial registers or in the peer-reviewed literature. A 2026 narrative review that stratified growth-hormone-axis peptides into evidence tiers placed pegylated mechano growth factor among the compounds for which human studies are entirely absent. The unconjugated peptide it derives from has its own in vitro literature, and that literature is itself contested.
Highest research phase reached: None identified. No published study of this conjugate in any system has been located.
Approved uses: None
Approval is compound-specific: No

Status as of September 22, 2026. This block is rendered from maintained fields, not from prose, so it cannot go stale in one place and stay current in another.

Chemical & Molecular Characteristics

No register carries the conjugate. There is no CAS registry number, no UNII, no PubChem compound identifier, no molecular formula and no molecular weight published for PEG-MGF by any public register. Every one of those fields is shown as unknown on this page, and the reason is the same in each case.

A molecular weight cannot be stated even in principle. It would be the mass of the peptide plus the mass of the polymer, and the polymer's mass is not fixed by the compound's name. Polyethylene glycol used in peptide conjugation spans a wide range of molecular weights and comes in linear and branched forms; the difference between two such conjugates of the same peptide can be several-fold in mass. A single figure would be a fabrication.

The peptide moiety is documented separately. The sequence YQPPSTNKNTKSQRRKGSTFEERK is carried under UNII Q86M4KXC2P, and a C-terminally amidated version under UNII Y65LH7J9BL. Those records describe the unconjugated peptides. They do not describe this substance, and they are cited here to identify the starting material rather than to characterise the product.

The certificate of analysis is the only record. For a compound with no register entry and no published characterisation, the analytical documentation supplied with a given lot is not merely the best record of what it contains — it is the only one.

Frequently Asked Questions

What is PEG-MGF?

The name describes a polyethylene glycol conjugate of the peptide called mechano growth factor — a 24-residue chain corresponding to the C-terminal E domain of the IGF-1Ec splice variant of the insulin-like growth factor 1 gene ^{[1, 2]}. Beyond that, the name specifies very little: it does not state the molecular weight of the polymer, whether it is linear or branched, what chemistry attaches it, or which residue it attaches to. Those parameters define the substance, and none of them is fixed by the name.

Has PEG-MGF been studied?

No study of the conjugate has been identified — not in humans, not in animals, not in cell culture. A 2026 narrative review that sorted growth-hormone-axis peptides into evidence tiers ranging from randomised trial data down to a complete absence of human studies placed pegylated mechano growth factor in the last of those tiers ^[5]. This page records that absence rather than filling it with evidence about a different compound.

Is PEG-MGF FDA approved?

No. No product containing this conjugate has been approved by the U.S. Food and Drug Administration for any indication, and none is known to have been submitted for approval.

How does PEG-MGF differ from MGF?

By the attached polymer, and by how much is known about it. MGF has a register record, a defined 24-residue sequence, a calculated mass and a substantial if contested in vitro literature. The conjugate has none of those. Any statement about what pegylation does to this particular peptide would be an extrapolation from the general behaviour of the technique rather than a measurement ^[4].

Why are the specification fields on this page blank?

Because no public register carries a record for the conjugate. There is no CAS registry number, no UNII, no PubChem compound identifier, no molecular formula and no molecular weight to publish. A molecular weight in particular cannot be stated even in principle: it is the sum of a known peptide and a polymer whose size is not specified by the compound's name. The convention on these pages is to publish unknown rather than a plausible figure.

What does pegylation do in general?

Attaching polyethylene glycol to a peptide or protein increases its hydrodynamic size, which typically slows renal clearance and proteolysis and so extends circulating half-life; it is one of the established half-life extension strategies in protein chemistry ^[4]. The size of that effect depends on the polymer, the attachment site and the molecule, and it is routinely accompanied by a loss of potency where the attachment interferes with target binding. None of that has been measured for this compound.

Does PEG-MGF have a known receptor?

No, and neither does the peptide it derives from. The original reports on the unconjugated peptide concluded that its activity did not proceed through the type 1 IGF receptor and inferred a different, unidentified receptor; no such receptor has since been reported ^[2]. A 2014 study at two pharmaceutical companies failed to reproduce the peptide's central in vitro effects altogether ^[3]. A conjugate of a peptide with no identified receptor inherits that uncertainty and adds to it.

Scientific References

Yang S, Alnaqeeb M, Simpson H, et al.. Cloning and characterization of an IGF-1 isoform expressed in skeletal muscle subjected to stretch Journal of muscle research and cell motility; 1996. PMID 8884603 doi:10.1007/BF00123364
Matheny RW Jr, Nindl BC, Adamo ML. Minireview: Mechano-growth factor: a putative product of IGF-I gene expression involved in tissue repair and regeneration Endocrinology; 2010. PMID 20130113 doi:10.1210/en.2009-1217
Fornaro M, Hinken AC, Needle S, et al.. 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 American journal of physiology. Endocrinology and metabolism; 2014. PMID 24253050 doi:10.1152/ajpendo.00408.2013
Tan H, Su W, Zhang W, et al.. Recent Advances in Half-life Extension Strategies for Therapeutic Peptides and Proteins Current pharmaceutical design; 2018. PMID 30727869 doi:10.2174/1381612825666190206105232
Dominikowski A, Rękoś Z, Olejarz M, et al.. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration Frontiers in endocrinology; 2026. PMID 42395176 doi:10.3389/fendo.2026.1822475

Every identifier above is resolved against PubMed, Crossref or ClinicalTrials.gov at build time, and the title returned by the register is compared with the title stored here. A page does not publish if a reference fails to resolve.

Research-Use Information

For in vitro research use only. This material is a laboratory reagent. It is not a drug, food, dietary supplement, or cosmetic and is not for human or veterinary use, including ingestion, injection, or any other administration. No information on this page describes or implies any effect in humans or animals. Sold only to researchers under our Terms of Sale.