PEG-MGF: what the evidence shows, status and safety
Summary
PEG-MGF is sold as a longer-acting mechano growth factor, but no published study has ever made, measured or tested such a molecule. The one peer-reviewed paper naming it is a 2026 review, which places it in its lowest evidence tier. Every published analysis of seized MGF material found an unpegylated variant instead. It is prohibited in sport and approved nowhere.
Key findings at a glance
- One peer-reviewed paper names it, and it is a review. A 2026 narrative review puts PEG-MGF in tier D with two other grey-market peptides. Tier D compounds, it writes, "have no peer-reviewed human studies and are supported only by preclinical extrapolation and grey-literature user narratives" [1].
- The half-life has never been measured. The same review sums up the pharmacology of PEG-MGF in one line: "pegylation extends stability, t½ not reported" [1].
- Searching for it returns almost nothing. A PubMed query for PEG-MGF returned one record on 16 September 2026, the review itself. The control query for mechano growth factor returned 2,386, so the search was working [2].
- No chemical identity is on record. No entry in the American chemical database, no registry number, no molecular formula and no stated position for the polyethylene glycol chain [3].
- No trial has ever been registered. A query of the American trial registry for PEG-MGF as an intervention returned zero studies [4].
- Three laboratories opened seized MGF vials and found no pegylated molecule. Ghent in 2012, Cologne in 2014 and Salt Lake City in 2017 each found a different unpegylated variant [5], [6], [7].
- Regulators use the name even though science does not. An American advisory committee is due to discuss "Mechano Growth Factor, Pegylated (PEG-MGF)" before the end of February 2027 [8].
- It is prohibited in sport at all times under the class covering growth factors, which names mechano growth factors in the plural [9].
What it is
PEG-MGF is a trade name, not a characterised substance. What is sold under it is described as a peptide with a chain of polyethylene glycol attached, supplied as a freeze-dried powder in vials.
The peptide half is real and well described. Mechano growth factor is the 24-unit tail of a splice variant of insulin-like growth factor 1. Its sequence is YQPPSTNKNTKSQRRKGSTFEEHK, translated from exons 4 to 6 of the human transcript [10], [6].
The other half is where the record stops. No source states how large the polyethylene glycol chain is, whether it is branched, or where on the peptide it sits. Without those three numbers there is no formula and no mass [3].
The idea has a documented origin. A 2005 patent application from University College London and the University of Illinois disclosed pegylation of the MGF peptide as a way to stabilise it. That family has lapsed, and no later patent claims a pegylated MGF as an active substance [11], [12].
Quick facts
| Field | Value | Ref |
|---|---|---|
| Name | PEG-MGF; no international non-proprietary name | [1] |
| Other names | Pegylated mechano growth factor; PEG MGF; "Mechano Growth Factor, Pegylated" in American regulatory wording | [1], [8] |
| Class | Claimed peptide-polymer conjugate; not classifiable with certainty, because the polymer part is unspecified | [1], [3] |
| Claimed peptide part | The 24-unit E-domain peptide of the IGF-1Ec splice variant, about 2.8 kDa | [10] |
| Formula and mass | Not definable; no source states the polymer mass or its attachment point | [3] |
| Half-life | Never reported, in any species | [1] |
| Route in studies | No study exists, so no route has been reported | [1], [4] |
| Status | Not approved anywhere; never entered development | [4], [8] |
| Origin of the concept | A lapsed 2005 patent application, which gives no half-life data for the pegylated form | [11], [13] |
| CAS, PubChem, UNII, InChIKey | None found on 16 September 2026 | [3] |
How it works
No published study has examined the mechanism of PEG-MGF. Every mechanistic claim made for it is borrowed from work on the unpegylated peptide, and the review that catalogues the substance says that borrowing is not allowed.
- Pegylation is a real technique. Attaching polyethylene glycol to a protein slows its clearance, which is why several licensed medicines use it [14].
- It is not a neutral addition. On insulin-like growth factor 1 it lowered receptor affinity. Receptor activation fell about two-fold with two attachment sites, and with a third it fell more than ten-fold in one cell line and about three-fold in the other. The rate at which the molecule attached to its binding proteins dropped ten-fold [15], [16].
- It can remove a function entirely. Every pegylated variant of that molecule lost the ability to trigger cell migration, while cell viability was untouched [16].
- The borrowed claims are explicitly blocked. Pegylation "fundamentally alters pharmacokinetics and tissue exposure", says the 2026 review, so native effects "cannot be assumed to apply to PEG-conjugated constructs" [1].
- The parent peptide has no settled mechanism either. Blocking the insulin-like growth factor 1 receptor with an antibody left its effect on muscle precursor cells intact. It acts elsewhere [17].
- One claim contradicts itself. Forum accounts describe local action without systemic effects, yet pegylation exists precisely to prolong systemic exposure. The review treats those accounts as anecdotal [1].
The groundwork on the unpegylated substance, including its biology and the open questions around it, is set out on its own page at MGF. This page is about what the added polymer changes, and about the absence of any answer to that question.
What the studies found
There is nothing to report for PEG-MGF itself. What follows is the search record, the closest comparable molecule and the laboratory analyses of the material actually in circulation.
Studies of PEG-MGF
No evidence Not one. The trial registry returned zero studies for PEG-MGF as an intervention. The control query for mechano growth factor returned 105 records, all of them word matches from research on insulin-like growth factor 1 and growth hormone [4].
No evidence The literature record is equally empty. A full-text search returned three hits, two of them coincidences. One was a methods paper using MGF as a model analyte, the other a nanoparticle study using MGF as a targeting tag [18], [19], [20].
No evidence The one substantive hit was the 2026 review. On efficacy it concludes that "claims that PEG-MGF reliably accelerates recovery or improves body composition in humans remain unproven, and robust RCTs in human populations are lacking" [1].
Pegylated IGF-1, the molecule that was actually developed
Phase 1 This is the reference case, and it is a different molecule. Roche made a recombinant human insulin-like growth factor 1 pegylated at a defined site, and tested it in 62 healthy volunteers in a randomised, double-blind, placebo-controlled study [14].
Phase 1 The half-life came out at 140 to 200 hours, with roughly dose-proportional exposure. The commonest adverse event was redness at the injection site, and no hypoglycaemia occurred [14].
Animal data In mice, that molecule injected into an injured muscle improved early recovery of force by 27 per cent against saline (p < 0.05). Fibre cross-sectional area was 13 per cent larger than with the unpegylated version (p < 0.05). Given systemically, neither worked [21].
That is what the evidence looks like when a pegylated member of this family is genuinely developed. For PEG-MGF, none of it exists.
What laboratories found inside seized vials
Analytical Ghent, 2012. A doping-control laboratory characterised two black-market preparations and identified an MGF analogue amidated at one end, distinguishable from the natural molecule by the transition m/z 717.8 to 431.1 [5].
Analytical Cologne, 2014. A full-length MGF offered through illegal channels was sequenced at a monoisotopic mass of 12,264.9 Da, with a terminal lysine missing and an arginine-to-histidine change at position 109. Adapted routine methods detected it from 0.25 ng/mL [6].
Analytical Salt Lake City, 2017. Confiscated ampoules contained the variant MGF R23H, which proved stable in plasma [7].
Three doping-control laboratories opened and characterised MGF material seized from the grey market between 2012 and 2017: Ghent, an amidated analogue; Cologne, a full-length variant with an arginine-to-histidine change; Salt Lake City, the variant MGF R23H. Three published analyses are the whole record, so the zero says nothing was found, not that nothing exists. Sources [5], [6], [7].
What is still unknown
- What the substance is. No polymer mass, no branching, no attachment point, and no published analysis of a traded product confirming that polyethylene glycol is present at all [3].
- What the body does with it. No half-life, no bioavailability, no distribution data, in any species [1].
- Whether it does anything. No published animal study of the pegylated form exists, and no human study of any kind [1], [4].
- Whether the immune system reacts to it. Pegylated drugs are routinely screened for anti-PEG antibodies during development. This one was never in development [22].
- Whether the cancer signal carries over. The proliferative concern documented for the unpegylated peptide has never been examined in a pegylated construct [1], [23].
Side effects and safety
There is no safety record for PEG-MGF, because there has never been a study that could produce one. The 2026 review records the position in the same words for every safety column of its table: no peer-reviewed human studies [1].
- Anti-PEG antibodies are the known problem of pegylated drugs. They appear regularly after systemic dosing. They also pre-exist in people who never received one, because polyethylene glycol is common in food and cosmetics [22], [24].
- They cause two things. The drug is cleared faster and stops working, and complement activation can produce hypersensitivity reactions ranging up to occasionally fatal anaphylaxis [22].
- The risk cannot be estimated in advance. Antibody levels vary between individuals and were shown to rise after pegylated lipid nanoparticle vaccines. Testing is a trial procedure, not something available outside one [25], [24].
- A proliferative signal sits with the parent peptide. In human prostate tissue, MGF was overexpressed in cancer and undetectable in normal epithelium. The synthetic peptide stimulated the growth of cancer cell lines [23].
- That signal runs through an unknown route. Silencing the insulin-like growth factor 1 receptor and the insulin receptor did not abolish the effect [23].
- The class carries the usual endocrine concerns. For peptides acting on this axis the 2026 review lists fluid retention, joint and muscle pain and altered glucose handling. It also states plainly that there are no human data for PEG-MGF [1].
- The vial is not reliable. Of 1,190 doping products seized at the Swiss border, fewer than 20 per cent contained the stated substance in the stated amount. Of those, 146, or 12 per cent, were labelled as peptide hormones or growth factors [26].
Contraindications cannot be listed, because listing them would require a safety profile that does not exist. No purity, sterility or endotoxin specification has been published, and there is no pharmacopoeia monograph [1], [3].
Why this page lists no doses
This page carries no amounts for PEG-MGF, in any unit. The reason is not mainly a legal one. It is that there is nothing to cite. No published study has given a pegylated MGF to a person or to an animal, so no study dose exists in the literature [1], [4].
The figures that circulate come from bodybuilding forums and a seller blog. The 2026 review that tabulates them says so in its own footnote, describing them as derived from online material that is not peer-reviewed and often internally inconsistent [1].
The legal picture reinforces the same conclusion. In Australia the substance class is prescription-only and possession without authority is prohibited; in Germany it is named in the annex to the anti-doping statute [27], [28].
Development and approval status
PEG-MGF has never been approved anywhere and never entered development. There is no sponsor, no investigational application and no preclinical programme. Checks across seven markets on 16 September 2026 found nothing [4], [29], [30], [31], [32].
Twenty-one years from a patent sentence to an advisory committee
- 2002The peptide is describedThe E-domain of MGF is shown to act on muscle precursor cells, apparently not through the IGF-1 receptor, ref [17]
- 2005Pegylation is proposedA patent application discloses pegylation of the MGF peptide as a stabilisation strategy, with no half-life data; the family later lapses, ref [11]
- 2012Ghent opens the vialsAn amidated MGF analogue is identified in two black-market preparations, ref [5]
- 2014Cologne sequences a variantA full-length MGF from illegal channels is characterised at 12,264.9 Da with an R109H change, ref [6]
- 2017Salt Lake City confirms the patternConfiscated ampoules contain MGF R23H; again nothing pegylated, ref [7]
- 2026The first and only paperA review names PEG-MGF and places it in tier D, with the half-life not reported, ref [1]
- 2027An advisory committee is dueAn American committee is to discuss the substance for the compounding bulk list before the end of February, ref [8]
- 2002 the E-domain peptide of mechano growth factor is characterised in muscle precursor cells [17].
- 2005 a patent application discloses pegylation of that peptide, without measuring it; the family lapses [11], [13].
- 2012 to 2017 three doping-control laboratories characterise seized MGF material and find unpegylated variants each time [5], [6], [7].
- May 2026 the American nomination list for compounding bulk substances carries mechano growth factor in category 3, nominated without adequate support. The word pegylated does not appear in the document [29].
- 2026 a narrative review becomes the first and only peer-reviewed publication to name PEG-MGF [1].
- Before the end of February 2027 an advisory committee is due to discuss the substance under the name "Mechano Growth Factor, Pegylated (PEG-MGF)" [8].
| Market | Status | Since or note |
|---|---|---|
| United States | Unapproved | Nominated for compounding |
| European Union | Unapproved | No assessment report |
| Germany | Unapproved | Named in doping annex |
| United Kingdom | Unapproved | Unlicensed |
| Australia | Prescription-only, by derivation | Schedule 4 and Appendix D as an insulin-like growth factor; the name PEG-MGF is not listed |
| Canada | Unapproved | No product record |
| Switzerland | Unapproved | None found |
The Australian entry is the strictest, and it is a derivation rather than a direct listing. The poisons standard does not name PEG-MGF. It places "insulin-like growth factors" as a class in Schedule 4 and in Appendix D item 5, where possession without authority is prohibited, and the claimed peptide is a fragment of one [27].
Import is separately restricted. Growth hormones and insulin-like growth factors require permission under the customs regulations, and an Australian disclosure document names PEG MGF under that item. That document could not be retrieved directly, so treat the naming as reported rather than verified [27], [33].
Two entries are weaker than the rest. The European and British registers could not be queried by machine. Those results are inferred from the absence of the substance everywhere else, not from a register match [30].
The wider legal picture is under are peptides legal and FDA-approved peptides.
Anti-doping
PEG-MGF is prohibited at all times, in and out of competition. It is not named on the 2026 list, and it does not need to be [9].
Section S2.3 lists "Mechano growth factors (MGFs)" in the plural and "Insulin-like growth factor 1 (IGF-1, mecasermin) and its analogues". The class heading adds "other substances with similar chemical structure or similar biological effect(s)" [9].
Everything in class S2 is a non-specified substance, which is the stricter category for sanctioning purposes. MGF has been treated as prohibited since 2005 [9], [6].
German law names the substance group directly. The annex to the anti-doping act lists "Mechano Growth Factor (MGF) und MGF-Varianten", and the closing clause of that annex extends the list to complexes and derivatives [28].
The quantity regulation sets the threshold at which acquisition, possession, trade and manufacture for doping purposes become punishable. For mechano growth factor and its variants it is 3 mg, twenty times lower than for mecasermin [34].
Each bar is a legal threshold, not a dose and not an amount used in any study. It is the quantity above which acquisition, possession, trade and manufacture for doping purposes become punishable under the German quantity regulation. No study amount exists for PEG-MGF in any unit. Source [34].
One claim deserves correcting. No dedicated detection method for a pegylated MGF has been published, but that is a gap in the method literature, not proof of anything. Published methods work from the peptide sequence, and laboratories have added each new variant as it appeared [6], [7].
The full picture is at peptides banned in sport.
Compared with related peptides
| Substance | What it is | Human evidence | Ref |
|---|---|---|---|
| PEG-MGF | Claimed pegylated form of an IGF-1 splice peptide | None; no registered trial | [1], [4] |
| MGF | The unpegylated peptide itself | See its own page | — |
| IGF-1 LR3 | Modified IGF-1 analogue, same grey-market group | Placed in the same tier D by the same review | [1] |
| HGH 191aa | Recombinant growth hormone, approved medicine | Large clinical programme; see its own page | — |
| Follistatin-344 | Myostatin-binding protein construct | See its own page | — |
The table shows the gradient. Growth hormone is an approved medicine with a regulatory file behind it, while the other four sit at descending levels of documentation [1].
PEG-MGF occupies the bottom of that gradient together with IGF-1 LR3. The same review assigns both to tier D and states that mechanistic plausibility for tier-D compounds does not constitute clinical evidence [1].
The contrast with pegylated IGF-1 is sharper still. That molecule was pegylated at a known site, measured in 62 volunteers and published. PEG-MGF shares only the word pegylated [14].
Common misconceptions
- "PEG-MGF is a characterised, longer-acting version of MGF." No paper has made or measured one. There is no registry entry, no registry number and no formula [1], [2], [3].
- "Pegylation extends the effect from minutes to days." That is a sales claim. The review records the half-life as not reported, and the 2005 patent gives targets rather than measurements [1], [11].
- "Buying PEG-MGF gets you pegylated MGF." Three published analyses of seized MGF material found unpegylated variants. Fewer than 20 per cent of seized doping products contain what the label states [5], [6], [7], [26].
- "It is the pegylated IGF-1 that was tested in humans." A different molecule. That one is recombinant IGF-1 pegylated at a defined lysine, with a published phase 1 study [14], [15].
- "A registry entry proves it is being trialled." The only hit under a loose search is NCT02375620, a phase 2 study of pegylated growth hormone in 96 children born small for gestational age, sponsored by Changchun GeneScience. A precise query returns zero [4].
- "It is not on the doping list, so it is allowed." The list defines classes. It names mechano growth factors in the plural and adds a catch-all for similar structures and effects [9].
- "Pegylation makes it invisible to testing." Unproven. No dedicated method has been published, which is not the same as being undetectable [6], [7].
- "The FDA is reviewing it, so approval is coming." The committee is discussing use as a compounding ingredient, which is not an approval route. Its advice does not bind the agency [8], [29].
- "MGF research applies to PEG-MGF." The review states the opposite in terms: effects seen with the native peptide cannot be assumed to carry over to pegylated constructs [1].
Frequently asked questions
What is PEG-MGF?
It is a trade name for an injectable product said to be mechano growth factor with a polyethylene glycol chain attached. Mechano growth factor is a 24-unit peptide cut from a splice variant of insulin-like growth factor 1. Whether the material sold under the name actually carries polyethylene glycol has never been confirmed by any published analysis.
Are there any human studies of PEG-MGF?
None. A query of the American trial registry for PEG-MGF as an intervention returned zero studies in September 2026. A 2026 review places the substance in its lowest evidence tier, described as having no peer-reviewed human studies and being supported only by preclinical extrapolation and user narratives.
Does pegylation really make PEG-MGF last longer?
Nobody has measured it. The 2026 review records the position in five words: half-life not reported. Pegylation does extend the life of other molecules, but it also changes how they bind their receptors, sometimes severely. For this product neither effect has ever been tested.
Is PEG-MGF the same as MGF?
No, and treating them as one substance is the most consequential mistake on this topic. The whole preclinical literature was produced with the unpegylated peptide, which has its own page at /peptides/mgf. The 2026 review states that effects seen with the native molecule cannot be assumed to apply to pegylated constructs.
What did laboratories find inside seized PEG-MGF and MGF vials?
Not pegylated material. A Belgian laboratory identified a C-terminally amidated MGF analogue in two black-market preparations in 2012. A German laboratory sequenced a full-length MGF with an arginine-to-histidine change in 2014. An American laboratory found the variant MGF R23H in confiscated ampoules in 2017. No pegylated molecule has appeared in any of them.
Is PEG-MGF legal?
It is not an approved medicine in any country checked. In Australia insulin-like growth factors sit as a class in Schedule 4 and in Appendix D, where possession without authority is prohibited and import requires permission; the name PEG-MGF itself is not listed, so that status is a derivation. In Germany the anti-doping statute names mechano growth factor and MGF variants directly, with a criminal threshold of 3 mg.
Is PEG-MGF banned in sport?
Yes, at all times, in and out of competition. The 2026 prohibited list names mechano growth factors in the plural under section S2.3, alongside insulin-like growth factor 1 and its analogues. It adds a catch-all for substances of similar structure or effect. Everything in class S2 counts as a non-specified substance.
Why is the FDA looking at PEG-MGF?
An advisory committee is due to discuss whether the substance may be used as a bulk ingredient in pharmacy compounding, before the end of February 2027. That is not an approval process, and the committee cannot bind the agency. The nomination list itself still carries only mechano growth factor, in the category for substances nominated without adequate support.
What are the safety concerns with PEG-MGF?
Three, none of them measured for this product. Pegylated drugs regularly provoke anti-PEG antibodies, which can abolish the effect or trigger severe hypersensitivity. The MGF peptide itself stimulated the growth of prostate cancer cells in culture. And seized doping products rarely contain what the label claims.
Why does this page give no doses for PEG-MGF?
Because none exist. No published study has administered a pegylated MGF to a human being or to an animal, so there is no figure to cite. The numbers circulating online come from bodybuilding forums, which the 2026 review describes as non-peer-reviewed and often internally inconsistent.
Sources
- Dominikowski A, Rękoś Z, Olejarz M, Szczepanek-Parulska E, Domin R, Ruchała M (2026). The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Frontiers in Endocrinology 17:1822475. PMID 42395176. PMCID PMC13322892. DOI 10.3389/fendo.2026.1822475. Full text read. The only peer-reviewed publication naming PEG-MGF; tier D classification, table 1 entry "pegylation extends stability, t½ not reported", section 3.4.4.1 on the limits of extrapolation, and the footnote identifying the tabulated protocols as forum and seller material.
- NCBI PubMed E-utilities, https://eutils.ncbi.nlm.nih.gov/entrez/eutils/, queried 16 September 2026. "PEG-MGF": 1 record, the review above. "pegylated mechano growth factor": 5 records, none about a pegylated MGF. "PEG-MGF muscle": 0. "MGF peptide half-life serum stability": 0. Control queries: "mechano growth factor" 2,386; "mechano growth factor doping detection" 19; "anti-PEG antibodies" 409.
- PubChem PUG-REST and autocomplete APIs, https://pubchem.ncbi.nlm.nih.gov/rest/pug/, queried 16 September 2026. Compound lookups for "PEG-MGF", "pegylated mechano growth factor" and "mechano growth factor" each returned HTTP 404, "No CID found that matches the given name"; autocomplete returned a total of zero for the first term. No CAS registry number, UNII, InChIKey, DrugBank or ChEMBL record was found for PEG-MGF on the same day.
- ClinicalTrials.gov API v2, https://clinicaltrials.gov/api/v2/studies, queried 16 September 2026. Intervention query "PEG-MGF": 0 studies. Control query "mechano growth factor": 105 studies, all word matches from insulin-like growth factor 1 and growth hormone research, none testing MGF or PEG-MGF. A looser term query returned three studies of pegylated growth hormone, including NCT02375620 in children born small for gestational age, sponsor Changchun GeneScience, phase 2, n = 96.
- Esposito S, Deventer K, Van Eenoo P (2012). Characterization and identification of a C-terminal amidated mechano growth factor (MGF) analogue in black market products. Rapid Communications in Mass Spectrometry 26(6):686-692. PMID 22328223. DOI 10.1002/rcm.6144. Doping-control laboratory, Ghent University. Two black-market preparations; the analogue differed from the reference standard by one mass unit because of a C-terminal amidation; diagnostic transition m/z 717.8 to 431.1. No pegylated molecule found.
- Thevis M, Thomas A, Geyer H, Schänzer W (2014). Mass spectrometric characterization of a biotechnologically produced full-length mechano growth factor (MGF) relevant for doping controls. Growth Hormone & IGF Research 24(6):276-280. PMID 25466910. DOI 10.1016/j.ghir.2014.10.004. Centre for Preventive Doping Research, Cologne. Monoisotopic mass 12,264.9 Da, terminal lysine absent, R109H substitution; detectable from 0.25 ng/mL after adapting routine methods. Records that MGF has been considered prohibited under the anti-doping rules since 2005, and that the synthetic 24-unit peptide derives from exons 4 to 6 of IGF-1Ec. No pegylated molecule found.
- Cox HD, Miller GD, Eichner D (2017). Detection and in vitro metabolism of the confiscated peptides BPC 157 and MGF R23H. Drug Testing and Analysis 9(10):1490-1498. PMID 28035768. DOI 10.1002/dta.2152. Sports Medicine Research and Testing Laboratory, Salt Lake City. Confiscated ampoules contained BPC 157 and MGF R23H; the latter was stable in plasma in vitro. No pegylated molecule found.
- US Food and Drug Administration. Meeting of the Pharmacy Compounding Advisory Committee, https://www.fda.gov/advisory-committees/pharmacy-compounding-advisory-committee/meeting-pharmacy-compounding-advisory-committee, content current as of 15 April 2026, retrieved 16 September 2026. States that a meeting will be held before the end of February 2027 and that the committee will discuss substances for inclusion on the 503A bulks list, listing "Mechano Growth Factor, Pegylated (PEG-MGF)". The only regulatory document found that uses the name.
- World Anti-Doping Agency. World Anti-Doping Code International Standard, Prohibited List 2026, in force 1 January 2026. Full text checked 16 September 2026. Section S2.3 lists "Mechano growth factors (MGFs)" and "Insulin-like growth factor 1 (IGF-1, mecasermin) and its analogues"; the class heading reads "PROHIBITED AT ALL TIMES (IN- AND OUT-OF-COMPETITION)", "All prohibited substances in this class are non-Specified Substances" and covers "other substances with similar chemical structure or similar biological effect(s)". A full-text search for "PEG" and "pegylat" returned no match.
- Zabłocka B, Goldspink PH, Goldspink G, Górecki DC (2012). Mechano-Growth Factor: an important cog or a loose screw in the repair machinery? Frontiers in Endocrinology 3:131. PMID 23125840. PMCID PMC3485521. DOI 10.3389/fendo.2012.00131. Full text read. Critical review by the group that first described the peptide. Gives the sequence YQPPSTNKNTKSQRRKGSTFEEHK, records that the endogenous existence of free E-domain peptides is unconfirmed, that the mechanism is unknown, and that synthetic E-domains benefit from chemical stabilisation, with no numerical half-life given anywhere.
- Goldspink G, Yang SY, Goldspink P; UCL Business Ltd and University of Illinois System. Mechano growth factor peptides and their use. WO2006097682A1, priority 18 March 2005, status ceased. Retrieved from patents.google.com on 16 September 2026. Description read. Discloses pegylation of the MGF peptide, preferably at one terminus, with any suitable polymer mass. Contains no quantitative half-life data for a pegylated MGF, only target values and plasma-stability blots at 0 and 30 minutes and 2 and 24 hours.
- Google Patents search interface, queried 16 September 2026. The phrase "pegylated mechano growth factor" matched 3 documents and "PEG-MGF" matched 4. None of them claims a pegylated MGF as an active substance; the mentions occur in lists of candidate agents within drug-delivery patents.
- Goldspink G, Yang SY, Goldspink P; UCL Business PLC and Board of Trustees of the University of Illinois. Mechano Growth Factor Peptides and Uses thereof. KR20080021588A, priority 18 March 2005, published 7 March 2008. Retrieved from patents.google.com on 16 September 2026. Family member of the same application; claims the natural 24-unit E-peptide and a variant carrying an arginine-to-histidine substitution, the same change later found in seized material.
- Kletzl H, Guenther A, Höflich A, Höflich C, Frystyk J, Staack RF, et al. (2017). First-in-man study with a novel PEGylated recombinant human insulin-like growth factor-I. Growth Hormone & IGF Research 33:9-16. PMID 28110155. DOI 10.1016/j.ghir.2017.01.001. RO5046013, pegylated at lysine 68. Single-centre, randomised, double-blind, placebo-controlled, ascending single dose, parallel groups, 62 healthy volunteers in France. Half-life 140 to 200 hours, approximately dose-proportional exposure, injection-site erythema as the commonest adverse event, no hypoglycaemia.
- Metzger F, Sajid W, Saenger S, Staudenmaier C, van der Poel C, Sobottka B, et al. (2011). Separation of fast from slow anabolism by site-specific PEGylation of insulin-like growth factor I (IGF-I). Journal of Biological Chemistry 286(22):19501-19510. PMID 21460230. PMCID PMC3103329. DOI 10.1074/jbc.M110.172189. Pegylation at lysine 68 lowered affinity for the IGF-1 and insulin receptors and slowed association with binding proteins, while extending half-life and reducing hypoglycaemia risk in vivo.
- Sivaramakrishnan M, Kashyap AS, Amrein B, Saenger S, Meier S, Staudenmaier C, et al. (2013). PEGylation of lysine residues reduces the pro-migratory activity of IGF-I. Biochimica et Biophysica Acta 1830(10):4734-4742. PMID 23800578. DOI 10.1016/j.bbagen.2013.06.012. Receptor phosphorylation was reduced about two-fold with two pegylation sites and more than ten-fold in one cell line with a third; association with binding proteins fell ten-fold; all variants lost the ability to trigger migration in the presence of IGFBP-3 and vitronectin complexes, with cell viability unchanged.
- Yang SY, Goldspink G (2002). Different roles of the IGF-I Ec peptide (MGF) and mature IGF-I in myoblast proliferation and differentiation. FEBS Letters 522(1-3):156-160. PMID 12095637. DOI 10.1016/s0014-5793(02)02918-6. The E-domain inhibited terminal differentiation and increased proliferation of muscle precursor cells; blocking the IGF-1 receptor with a specific antibody showed that the effect runs through a different route.
- Europe PMC REST full-text search, https://www.ebi.ac.uk/europepmc/webservices/rest/search, queried 16 September 2026. Phrase search "PEG-MGF" returned 3 hits, "pegylated MGF" 1 and "pegylated mechano growth factor" 2. Two of the three hits are the false positives listed above.
- Peng Z, Bu J, McLuckey SA (2017). The Generation of Dehydroalanine Residues in Protonated Polypeptides: Ion/Ion Reactions for Introducing Selective Cleavages. Journal of the American Society for Mass Spectrometry 28(9):1765-1774. PMID 28497355. PMCID PMC5681889. DOI 10.1007/s13361-017-1672-5. Control source, false positive. Returned by a full-text search for "pegylated MGF"; a methods paper that uses MGF only as a model analyte. No pegylated MGF.
- Malhotra M, Tomaro-Duchesneau C, Saha S, Prakash S (2013). Intranasal, siRNA Delivery to the Brain by TAT/MGF Tagged PEGylated Chitosan Nanoparticles. Journal of Pharmaceutics 2013:812387. PMID 26555995. PMCID PMC4590831. DOI 10.1155/2013/812387. Control source, false positive. The pegylated component is the chitosan nanoparticle; MGF serves only as a targeting tag. No pegylated MGF.
- Martins KJ, Gehrig SM, Naim T, Saenger S, Baum D, Metzger F, Lynch GS (2013). Intramuscular administration of PEGylated IGF-I improves skeletal muscle regeneration after myotoxic injury. Growth Hormone & IGF Research 23(4):128-133. PMID 23608055. DOI 10.1016/j.ghir.2013.03.002. Mouse tibialis anterior. Local pegylated IGF-I on day 4 after injury improved normalised force by 27 per cent against saline (p < 0.05); unpegylated IGF-I given locally had no effect and systemic administration of either was ineffective. Fibre cross-sectional area was 13 per cent larger than with the unpegylated form (p < 0.05).
- Kozma GT, Shimizu T, Ishida T, Szebeni J (2020). Anti-PEG antibodies: Properties, formation, testing and role in adverse immune reactions to PEGylated nano-biopharmaceuticals. Advanced Drug Delivery Reviews 154-155:163-175. PMID 32745496. DOI 10.1016/j.addr.2020.07.024. Anti-PEG IgG and IgM cause loss of effect through accelerated blood clearance and hypersensitivity reactions up to occasionally fatal anaphylaxis, both driven by complement activation.
- Armakolas A, Philippou A, Panteleakou Z, Nezos A, Sourla A, Petraki C, Koutsilieris M (2010). Preferential expression of IGF-1Ec (MGF) transcript in cancerous tissues of human prostate. The Prostate 70(11):1233-1242. PMID 20564425. DOI 10.1002/pros.21158. MGF was overexpressed in prostate cancer tissue and undetectable in normal prostate epithelial cells; the synthetic E-peptide stimulated growth of PC-3 and LNCaP cells and activated ERK1/2 without affecting Akt. Silencing the IGF-1 receptor and the insulin receptor did not abolish the mitogenic effect.
- Gaballa SA, Shimizu T, Ando H, Takata H, Emam SE, Ramadan E, et al. (2024). Treatment-induced and Pre-existing Anti-PEG Antibodies: Prevalence, Clinical Implications, and Future Perspectives. Journal of Pharmaceutical Sciences 113(3):555-578. PMID 37931786. DOI 10.1016/j.xphs.2023.11.001. Anti-PEG antibodies are reported regularly after systemic administration of pegylated therapeutics and pre-exist in healthy people never treated with one; American industry guidance recommends screening for them in clinical trials of pegylated proteins.
- Ju Y, Lee WS, Pilkington EH, Kelly HG, Li S, Selva KJ, et al. (2022). Anti-PEG Antibodies Boosted in Humans by SARS-CoV-2 Lipid Nanoparticle mRNA Vaccine. ACS Nano 16(8):11769-11780. PMID 35758934. DOI 10.1021/acsnano.2c04543. Demonstrates that anti-PEG antibodies in humans are boosted by pegylated lipid nanoparticles.
- Weber C, Krug O, Kamber M, Thevis M (2017). Qualitative and Semiquantitative Analysis of Doping Products Seized at the Swiss Border. Substance Use & Misuse 52(6):742-753. PMID 28156209. DOI 10.1080/10826084.2016.1263665. 1,190 seized products; 146 (12 per cent) labelled as peptide hormones or growth factors. Fewer than 20 per cent of all products contained the stated substance in the stated amount, and unapproved substances were detected. The authors describe the pharmaceutical quality as substandard.
- Poisons Standard February 2020 (Standard for the Uniform Scheduling of Medicines and Poisons; legislative instrument F2020L00017), Australia, dated 23 December 2019. Full PDF read on 16 September 2026. Schedule 4 contains "INSULIN-LIKE GROWTH FACTOR I." and "INSULIN-LIKE GROWTH FACTORS except when separately specified in this Schedule."; the substance index records "Schedule 4 / Appendix D, Item 5"; paragraph 3.5(1)(b) reads "A person must not … knowingly have in his or her possession a poison listed in Appendix D paragraph 5 without authority." A newer compilation could not be retrieved by machine.
- Annex to section 2(3) of the German Anti-Doping Act (AntiDopG), official citation BGBl. 2023 I no. 67, 1-5. Full text read on 16 September 2026. Section II.3 lists "Mechano Growth Factor (MGF) und MGF-Varianten" alongside mecasermin, IGF-1 analogues and thymosin beta-4. The closing clause reads "Die Aufzählung schließt die verschiedenen Salze, Ester, Ether, Isomere, Mischungen von Isomeren, Komplexe oder Derivate mit ein."
- US Food and Drug Administration. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act, version updated 14 May 2026, https://www.fda.gov/media/94155/download, read on 16 September 2026. "Mechano growth factor (MGF)" appears in category 3, bulk drug substances nominated without adequate support. A full-text search for "pegylat", "PEG-" and "polyethylene" returned no match anywhere in the document.
- Register checks of 16 September 2026 across the remaining markets. The European and British registers could not be queried by machine, returning HTTP 401, 403 and 404 respectively, so those entries are inferred rather than matched; no Swissmedic authorisation was found. Details and limitations are recorded in the verification notes for this page.
- Health Canada Drug Product Database API, https://health-products.canada.ca/api/drug/activeingredient/, queried 16 September 2026. "PEG-MGF" and "MECHANO GROWTH FACTOR" each returned an empty result; the control query "MECASERMIN" returned a record, so the interface was working.
- openFDA APIs, https://api.fda.gov/, queried 16 September 2026. The approvals, labelling and enforcement endpoints each returned no record for "PEG-MGF" or for "mechano growth factor"; a control query for mecasermin returned records. No American labelling document and no recall exists for either name.
- Therapeutic Goods Administration, Australia, freedom-of-information release document foi-1103-1819-01. Names PEG MGF as an import prohibited under Schedule 7A item 3 of the Customs (Prohibited Imports) Regulations 1956, which covers natural and manufactured growth hormones including insulin-like growth factors. The regulation text was read from a 2007 compilation on 16 September 2026; direct retrieval of the release document was blocked by the server, so its wording is reported from the search index rather than verified in the original.
- Regulation on the determination of the non-minor quantity of doping agents (Dopingmittel-Mengen-Verordnung, DmMV), Germany, https://www.gesetze-im-internet.de/dmmv_2023/DmMV.pdf, read on 16 September 2026. Section II.3 sets the threshold for "Mechano Growth Factor (MGF) und MGF-Varianten" at 3 mg, against 60 mg for mecasermin, 3 mg for IGF-1 analogues and 100 mg for thymosin beta-4 and its derivatives.
Cite this page
The facts on this page were checked on 16 September 2026. Two points remain open: the European and British register entries rest on inference rather than a database match, and the Australian import naming is reported from a document that could not be retrieved directly.
myPeptides Research & Editing. (2026). PEG-MGF: what the evidence shows, status and safety. Version 1.0, 16 September 2026. myPeptides Peptide Register. Retrieved from https://mypep.app/peptides/peg-mgf
How pages in this register are compiled and graded is described under methodology; the full register is at peptides.
| Version | Date | Change |
|---|---|---|
| 1.0 | 2026-09-16 | Initial publication |
Last verified: 16 September 2026. Next review: on publication of any study of a pegylated MGF, on the outcome of the announced advisory committee meeting, or on any change to the anti-doping classification.