Mechano Growth Factor (MGF): what the studies show, status and safety
Summary
Mechano growth factor is two things under one name. The body makes a splice variant of the growth factor IGF-1, called IGF-1Ec, when muscle is stretched or damaged. The grey market sells a synthetic 24-building-block piece of that protein, usually carrying a swapped building block. No human being has ever received either one in a study of any kind, and laboratory tests show the short peptide does not switch on the IGF-1 receptor. Sport bans it by name, and German law sets one of its lowest criminal thresholds for it.
Key findings at a glance
- Nobody has ever been given it. Three searches of the world trial register on 16 September 2026 returned no study in which MGF was administered to a person, registered or published [1].
- The peptide people buy does not activate the IGF-1 receptor. Across concentrations from 0.0625 to 1000 nanomoles per litre, neither the human MGF peptide nor the stabilised version produced any measurable response. IGF-1 reached half its maximum at 0.86 nanomoles per litre in the same test [2].
- The full protein does activate it, and the insulin receptor too. Material sold as full-length MGF drove the IGF-1 receptor 89-fold, against 77-fold for IGF-1. It drove the insulin receptor B 292-fold, against 98-fold for human insulin [2].
- Two drug companies tried to reproduce the muscle effect and could not. At two pharmaceutical companies, researchers applied the peptide to human and mouse muscle cells at concentrations up to 500 nanograms per millilitre. It raised neither their growth nor their maturing into fibres, while mature IGF-1 did both in the same cells [3].
- One building block differs from the body's own version. The natural Ec domain ends in GSTFEERK, the researched and confiscated peptide in GSTFEEHK. Anti-doping laboratories call the seized material MGF R23H [4], [5].
- The free peptide has never been found in a living body. A critical review records that no such product of the IGF-1 gene has been isolated from cells, culture fluid, animal tissue or body fluid [6].
- Named on the banned list and in German criminal law. Section S2.3 of the 2026 Prohibited List carries its own entry for mechano growth factors [7]. The German threshold for a non-trivial quantity is 3 milligrams [8].
- A cancer signal runs through the literature. The same peptide appears in several independent studies as a growth and progression factor in prostate cancer, and no cancer-risk study has ever been done [9], [10].
What it is
MGF is not one substance. The body's version, IGF-1Ec, is a 158-building-block precursor protein made from the IGF-1 gene on chromosome 12. Muscle produces it after stretch or damage, and it is cut into mature IGF-1 plus a tail piece known as the E domain [11], [5].
The substance sold and studied under the name MGF is only that tail piece, synthesised in a laboratory: 24 building blocks, no ring, no sugars. Geoffrey Goldspink and Shi Yu Yang described the splice variant in stretched rabbit muscle in 1996, at the Royal Free Hospital in London [11].
Two details matter more than they look. The free tail piece has never been isolated from any living tissue [6]. And the synthetic version almost always differs from the natural one at position 23, which is why anti-doping chemists write it as MGF R23H [4].
Whether that swap was meant as a stabilising change is not documented. The papers describe a stabilised synthetic analogue without explaining the substitution, and no publication was found that states a reason for it [12], [13].
Quick facts
| Other names | IGF-1Ec, IGF-1 Ec isoform, MGF-24aa-E peptide, MGF-C25E, Ec peptide, MGF R23H [4], [14] |
| Class | Splice variant of IGF-1, and a synthetic fragment of its tail piece; not a hormone in its own right [12] |
| Sequence, grey-market peptide | YQPPSTNKNTKSQRRKGSTFEEHK, 24 building blocks [15] |
| Sequence, body's own tail | YQPPSTNKNTKSQRRKGSTFEERK, the last 24 of 158 building blocks [5], [16] |
| Formula and mass, calculated | C121H194N40O40, 2849.12 daltons average; the natural version C121H199N41O40, 2868.16 daltons |
| Half-life in people | Never published [17] |
| Status | Approved nowhere, for any condition [18], [19], [20] |
| Discovered by | Geoffrey Goldspink and Shi Yu Yang, University of London, 1996 [11] |
| Gene and protein entry | IGF1, chromosome 12q23.2; UniProt P05019-4 [5] |
| CAS, PubChem, UNII | None exists for either form [21] |
How it works
The idea behind MGF is that a short burst of this splice variant wakes up dormant repair cells in muscle, before the ordinary form of IGF-1 takes over the building work. The splicing is real and well documented. What the free peptide does, and whether it exists at all, is not.
- It does not act through the IGF-1 receptor. This is the firmest single finding on the page. Tested directly on human receptors, the peptide produced no response at any concentration [2].
- It may work inside the cell rather than on its surface. Heart muscle cells took it up quickly and concentrated it in the nucleus, without the IGF-1 receptor being switched on [22].
- It may signal through the ERK pathway, in some cells. In prostate cancer cells it switched on ERK1/2 and left the Akt pathway untouched. Silencing the IGF-1 and insulin receptors did not abolish the effect [9]. In heart muscle cells a later industrial team looked for the same switching and saw none, from either the plain or the stabilised peptide [3].
- The active part may be the very end of the chain. Breaking the human peptide into fragments traced the activity to its last four building blocks, which is exactly where the grey-market version differs from the natural one [14].
- Its effects appear to be species-specific. The human peptide stimulated human cells but never mouse muscle cells; the mouse version behaved the other way round [14].
- A phosphate site may govern the heart effects. A site at building block 18 sits inside a suspected docking region, and mimicking or blocking it changed heart function in mice differently [23].
The muscle finding itself did not hold up when others tested it. The effect on muscle cells, the observation the whole idea rests on, was not reproduced at two pharmaceutical companies, whose authors closed by questioning whether the peptide has a physiological role at all [3].
One caveat runs through the whole field. What was observed was a change in messenger RNA. What was injected, decades later, was a synthetic peptide. That the first produces the second is an assumption. A 2012 review states plainly that the existence of the naturally functioning E peptides has not been confirmed [12].
This separates MGF from its shelf neighbours. IGF-1 LR3 is a modified version of the mature hormone and binds the IGF-1 receptor tightly. Mecasermin, the approved form of IGF-1, is the mature part itself. MGF is the piece that gets cut off [2].
What the studies found
There are no trials. Not one registered or published study has given MGF or its E peptide to a human being, so everything below comes from animals, from cells in a dish or from receptor tests [1].
The receptor test that settles the mechanism
In vitro Researchers in Rotterdam measured receptor switching directly, across an equal-molar range from 0.0625 to 1000 nanomoles per litre. Neither the human MGF peptide nor the stabilised Goldspink version activated the IGF-1 receptor at any point [2].
The authors put it in one sentence: "No IGF-IR activation was observed by human MGF and Goldspink-MGF." [2]
The same run tells the opposite story for the full protein. Material recovered from a product offered to athletes drove the IGF-1 receptor 89-fold, against 77-fold for IGF-1. It needed nine times the concentration to reach half maximum, at 7.83 against 0.86 nanomoles per litre [2].
It also hit both insulin receptors, and hit one of them hard: 292-fold maximal stimulation of insulin receptor B, against 98-fold for human insulin itself. That is a blood-sugar signal attached to anything sold as full-length material [2].
Maximal receptor activation measured in one equal-molar titration from 0.0625 to 1000 nmol/l. The 24-building-block peptide gave no measurable response at any concentration. Source [2].
The replication that failed
In vitro Two pharmaceutical companies set out to confirm the claims made for the peptide, since a muscle-repair drug would have been worth having. Concentrations up to 500 nanograms per millilitre failed to increase the growth of mouse C2C12 cells or of primary human skeletal muscle cells, and the peptide did not hold back their fusion into muscle fibres either. Mature IGF-1 and the full-length IGF-1Eb protein produced a clear growth response in the same cells [3].
The same group then tried primary mouse muscle stem cells, in case the cultured lines had lost the response. That showed nothing either. A final test looked in heart muscle cells for the ERK switching others had reported, and found none from the plain peptide or from a stabilised version, while IGF-1 gave a strong response [3].
This is the most important negative result on the page, because it sits directly against the claim the substance is sold on.
Human muscle cells in a dish
In vitro Cells taken from donors of three age groups were exposed to the 24-building-block peptide. In newborn and young adult cells it extended how long they kept dividing and delayed their ageing. In cells from old donors it did neither [24].
That result cuts against the story usually told about this peptide. The population it is marketed to is the one in which it failed to do anything measurable. It is also the finding the industrial replication looked for in the same kind of cells and did not see [3].
Gene activity after weight training
Controlled training study, no substance given Twenty-four volunteers trained for six weeks in two groups, with muscle samples taken before and after. MGF gene activity rose by 1160 percent in one group and 59 percent in the other. IGF-1 rose 335 percent in group A only [25].
This is a measurement of the body's own gene, in the person's own muscle. It says nothing about what happens when a synthetic peptide is injected, and it is routinely quoted as though it did.
The heart studies
Animal data Sheep given a small-particle heart attack and treated with 200 nanomolar E domain had 35 percent less compromised muscle after eight days, with no detectable cleaved caspase 3 [26].
In mice, the peptide softened the loss of pumping function and delayed decline after a blocked artery. One study delivered it from polymer rods roughly 100 micrometres long, implanted directly into the heart muscle, which lowered mortality [22], [13], [15].
Timing changed the result. Given within 12 hours, it slowed the decline but did not prevent abnormal thickening. Given from week eight, it improved pumping mainly by lowering vascular resistance [13].
Nerve, tendon and cartilage
Animal data In a motor neurone disease model, both IGF-1 and MGF improved hind-limb strength, with significantly more motor neurones surviving under MGF. The animals received a plasmid carrying the gene, not the peptide [27].
Animal data In rats, the C-terminal peptide protected dopamine-producing neurones and switched on the protective enzyme haem oxygenase-1 [28]. In injured Achilles tendons, 1000 nanograms per millilitre raised the function index and stiffness against saline [29].
Animal data In an arthritis model, pre-treatment slowed cartilage breakdown and raised type II collagen at four and six weeks. It appeared to work through the PI3K-Akt and MEK-ERK pathways [30].
The cancer findings
In vitro and animal data This line of work is the largest single body of evidence about the peptide, and it is the one grey-market pages leave out. IGF-1Ec is strongly expressed in prostate cancer tissue and in pre-cancerous lesions, and not at all in normal prostate cells [9].
Adding the synthetic E peptide made cancer cells grow faster. Making normal prostate cells overproduce it and implanting them in mice raised the rate at which they spread [10].
In human biopsies, how much IGF-1Ec a tumour expressed tracked its stage [10]. Raised expression has also been reported in endometriosis, endometrial cancer, colon polyps of increasing severity and bone cancer [31], [32], [33].
What is still unknown
- Everything about people. No dose, no blood levels, no safety data, no half-life, by any route [1], [17].
- Whether the free peptide exists in the body at all. It has never been isolated from cells, culture fluid, tissue or fluid [6].
- Whether animal findings transfer. Human and mouse versions were inactive in each other's cells, and the splice insert differs by three base pairs between the species [14], [24].
- Whether it causes cancer. No study of that question has been run, despite the expression findings [10].
- Why the muscle findings did not replicate. Neither the original groups nor the industrial team has explained the contradiction, and no further attempt has been published [3].
- What injecting under the skin does. Every animal study used a different route, and several used a gene construct or an implant [27], [15].
- A widely repeated muscle figure. Grey-market pages quote a gain of 20 to 25 percent after a plasmid injection. The searches behind this page could not trace that figure to any primary publication.
Side effects and safety
There is no safety record, because no person has ever been given the substance in a study. An empty file is not a clean one, and in this case the surrounding evidence points somewhere uncomfortable [1].
- The cancer signal is the main concern. Several independent groups describe the Ec peptide as a growth and progression factor in prostate cancer, with a link to how far tumours spread in mice [9], [10].
- Nobody knows what is in the vial. Confiscated goods have contained an amidated analogue, a version labelled R23H, and a 12,264.9-dalton protein with a modified end. Three different substances, one name [34], [35], [4].
- Anything sold as full-length carries a blood-sugar risk. That form strongly activates both insulin receptors, which the short peptide does not. A buyer cannot tell the two apart [2].
- Purity and immune reactions are unquantified. The United States regulator, writing about the polymer-attached form, notes a significant immunogenicity risk for certain routes and difficulty characterising the active ingredient [36].
- Attempts to dodge the ban create unknown molecules. A 2012 review warns that illegal manufacture of MGF mimetics yields analogues of unknown properties and potentially serious effects [12].
The file also lacks a confirmed effect to weigh any risk against. The muscle-cell finding that made the peptide interesting did not survive an attempt to reproduce it at two pharmaceutical companies [3].
There are no contraindications and no interaction warnings on file, because no authority has ever reviewed a product label for this substance. The discovering group itself flagged the problem early. In 2008 Goldspink, Wessner and Bachl wrote that the hypertrophy claim clearly has potential for abuse. It had already attracted the attention of body builders, they added [37].
The data gaps are total. There is no pharmacokinetics, no toxicity study of any duration and no reproductive work. There is no cancer-risk study, no immune data for the plain peptide and no long-term observation.
Doses used in studies
These are the doses used in the cited studies, listed for reference. They are not a recommendation.
Every line below comes from an animal, from cells in a dish or from a receptor test. There is no human line, because no human study exists.
| Study | Model | Dose | Route | Frequency | Duration | Ref |
|---|---|---|---|---|---|---|
| Carpenter 2008 | Sheep, small-particle heart attack | 200 nanomolar per substance | Not stated in the abstract | Not stated in the abstract | Read at 8 days | [26] |
| Pena 2015 | Mice, blocked coronary artery | About 0.1 ng per rod, around 10,000 rods; 1 µg in the comparison group | Rods into heart muscle; comparison into muscle | Once, released over 2 weeks | Followed to 10 weeks | [15] |
| Solis 2022 | Mice | Lowest step reported 2.25 mg/kg per day | Not stated in the abstract | Daily | 2 weeks | [23] |
| Zhang 2016 | Rats, injured Achilles tendon | 1000 ng/ml | Locally at the tendon | Not stated in the abstract | Not stated in the abstract | [29] |
| Papageorgiou 2016 | Human PC-3 cells | Active window 5 to 50 nmol/l, only at 10 percent serum | Added to the medium | Not applicable | Not applicable | [14] |
| Janssen 2016 | Human receptor assay | Titration 0.0625 to 1000 nmol/l | Not applicable | Not applicable | Not applicable | [2] |
Animal amounts in milligrams per kilogram cannot be scaled to people, and here the objection is sharper than usual. The human and mouse versions of this peptide were inactive in each other's cells. The human one worked only inside a narrow window that depended on the culture conditions [14].
Development and approval status
MGF never entered clinical development. There was no sponsor, no first-in-human study and no register entry naming it as a test substance. It moved from basic research straight to the grey market [1].
From a stretched rabbit muscle to a banned substance
- 1996The splice variant is describedStretched rabbit muscle, Royal Free Hospital, ref [11]
- 1999Stretch, not contraction, is the triggerElectrical stimulation alone changed nothing, ref [38]
- 2003The satellite-cell paper appearsTiming of messenger RNA, no peptide given, ref [39]
- 2005Sport prohibits the substance classRecorded by anti-doping researchers, ref [35]
- 2008The discoverers name the abuse potentialRef [37]
- 2010A review notes the free peptide was never isolatedRef [6]
- 2012 and 2014Black-market goods are characterisedAn amidated analogue, then a 12.3 kDa protein, refs [34], [35]
- 2016The receptor question is answeredNo IGF-1 receptor activation by the short peptide, ref [2]
- 2023German law sets the threshold at 3 mgRef [8]
- 2026Named on the banned list, approved nowhereRefs [7], [18], [19]
- 1996 — the splice variant is found in stretched rabbit muscle [11].
- 1999 — stretching drives the gene; electrical stimulation alone does not [38].
- 2001 — older rats express far less of it, and their repair markers stay flat [40].
- 2003 — the most-quoted study measures messenger RNA timing after muscle damage [39].
- 2004 — growth hormone turns out to raise it too, so the trigger is not only mechanical [41].
- 2005 — the substance class becomes prohibited in sport [35].
- 2016 — the receptor test shows the short peptide activates nothing [2].
- 2026 — still approved nowhere, still named on the banned list [7], [18].
| Market | Status | Note | Ref |
|---|---|---|---|
| United States | Not approved | Nominated for compounding without adequate support | [19], [36], [42] |
| European Union | Not approved | No authorisation | [18] |
| Germany | Not approved | Named in anti-doping law | [43] |
| United Kingdom | Not approved | Not a controlled drug | [44] |
| Australia | Prescription-only | Possession an offence, by class | [45] |
| Canada | Not approved | No database entry | [20] |
| Switzerland | Not approved | Consignments held at the border | [46] |
Every register query behind this table was run on 16 September 2026. Each carried a control search for mecasermin that returned results in the same call [19], [18], [20].
Two entries need qualifying. The Australian listing is a class entry for insulin-like growth factors, not the name MGF. Placing MGF there is therefore an inference. The consequence, that possession without authority is an offence, is not [45].
The United States finding needs stating precisely. Plain MGF was put forward as an ingredient for pharmacy compounding and placed in the category for substances nominated without adequate support, where it still sat when that list was updated on 14 May 2026 [42]. The polymer-attached form went the other way, into the category for substances that raise significant safety concerns, and that nomination was then withdrawn [36]. Neither route leads to a lawful medicine.
Switzerland has acted against this family. On 22 June 2026 the customs, medicines and anti-doping agencies jointly checked 46 peptide consignments. They held 23 back, 21 of them classed as doping material, around 80 percent arriving from Poland [46].
Anti-doping
MGF is banned in sport at all times, in and out of competition, and it is banned by name. Section S2.3 of the 2026 Prohibited List reads "Mechano growth factors (MGFs)" as its own bullet, alongside the IGF-1 entry rather than underneath it [7].
That wording removes an argument before it starts. Whether a splice variant counts as an IGF-1 analogue never has to be decided, because the plural covers every version. It is a non-specified substance, the stricter category, and has been prohibited since 2005 [7], [35].
German law goes further than a sporting ban. The annex to the anti-doping act names "Mechano Growth Factor (MGF) und MGF-Varianten" [43]. The accompanying regulation sets the non-trivial quantity at 3 milligrams [8].
For comparison in the same table: IGF-1 analogues also 3 milligrams, growth-hormone releasing peptides 1.5, somatropin 16, mecasermin 60, thymosin beta-4 100 [8]. Acquiring or possessing that quantity for doping a human being is a criminal matter, whether or not anyone competes.
Non-trivial quantities set by the 2023 regulation, section II.3. MGF sits at the bottom end of the whole table. Source [8].
Detection is routine and has been for over a decade. A black-market analogue was characterised in Ghent in 2012. A fragment transition at m/z 717.8 to 431.1 separates it from the body's own molecule [34]. A product advertised as undetectable was characterised in Cologne in 2014 and folded into testing down to 0.25 nanograms per millilitre [35], [47].
The wider picture for this family is at peptides banned in sport.
Compared with related peptides
| Peptide | What it is | Approval | Anti-doping | What sets it apart |
|---|---|---|---|---|
| Mechano Growth Factor | Tail piece of an IGF-1 splice variant | None, anywhere [18], [19] | Named, S2.3 [7] | Does not activate the IGF-1 receptor at all [2] |
| PEG-MGF | The same peptide with a polymer chain | None; put forward for compounding, then withdrawn [36] | Covered by the same entry [7] | The only form a regulator has set out written safety concerns for [36] |
| IGF-1 LR3 | Modified mature IGF-1 | None [19] | Named, S2.3 [7] | Binds the IGF-1 receptor tightly, which MGF does not [2] |
| HGH 191AA | The whole growth hormone | Approved as somatropin [19] | Named, S2 [7] | Raises MGF gene activity in muscle by itself [41] |
| Follistatin-344 | A natural blocker of muscle-growth brakes | None [19] | Covered by the class heading [7] | Works on a separate pathway, not through IGF-1 |
| Tesamorelin | Copy of the natural releasing hormone | Approved [19] | Named, S2 [7] | The only prescription medicine in this table besides somatropin |
| Ipamorelin | Prompts release of the body's own hormone | None [19] | Named, S2 [7] | Acts on the pituitary, a target MGF has never been shown to touch |
Three things stand out. MGF is the only entry here with no receptor of its own: the one it is assumed to use was tested and ruled out [2].
It is also the only one that never reached a first-in-human study, not even a failed one. Follistatin-344 at least has gene-therapy trials behind it, and tesamorelin has an approval [1].
And the closest comparison people actually intend is usually mecasermin, the approved form of IGF-1. That is the mature part of the same precursor protein. It is licensed in the European Union and the United States for a rare growth disorder [18], [19]. MGF is the piece that gets discarded when mecasermin is made.
Common misconceptions
- "It is a natural peptide, so injecting it only adds what the body makes." Wrong twice over. The free peptide has never been isolated from any organism, and the material sold ends in GSTFEEHK where the body's own ends in GSTFEERK [6], [4], [5].
- "It works like IGF-1, only locally." It does not work like IGF-1 at all. Across a 16,000-fold concentration range it produced no IGF-1 receptor activation, and blocking that receptor with antibodies or silencing it did not stop its effects in cells [2], [14], [9].
- "The registers list over a hundred studies." They list 105 records matching the words growth factor. Every one concerns IGF-1 as a marker, recombinant IGF-1, growth hormone or cancer antibodies. A search for IGF-1Ec returns exactly one observational study of blood levels in cancer patients [1].
- "Animal studies show what MGF injections do." The most-quoted study gave no peptide at all and measured messenger RNA. The motor neurone work injected a gene construct. The heart work partly used implanted polymer rods [39], [27], [15].
- "Rodent results carry over to humans." For this peptide they demonstrably do not. Tested head to head, the human version did nothing in mouse muscle cells and the mouse version did nothing in human cells [14].
- "It is harmless because it acts locally and briefly." The safety file is empty, and the one signal in it runs the other way: repeated findings of this peptide as a cancer growth and progression factor, with no cancer-risk study to weigh against them [9], [10].
- "It cannot be detected, so it is safe to use in sport." It has been detectable in routine methods since 2012, down to 0.25 nanograms per millilitre for one form, and the confiscated R23H version proved stable in plasma [34], [35], [4].
- "The half-life is a few minutes, so timing follows from it." No half-life has ever been measured or published for either form. The figure repeated online traces to no primary study. What the literature offers is a prediction of a very short life for the body's own version, and an explicit note that none is reported [12], [17].
- "A research-use-only label keeps the purchase lawful." It changes nothing in any of the three regimes that apply. The German threshold works regardless of labelling, Australian law bans possession by class, and the United States treats goods marketed for human use as unapproved new drugs [8], [45], [48].
Frequently asked questions
Has MGF ever been tested in people?
No. Three searches of the world trial register on 16 September 2026 found no study in which MGF was given to a human being. One search returns 105 records, but every one of them is about IGF-1 as a blood marker, about recombinant IGF-1, about growth hormone or about cancer antibodies. The search engine is matching the words growth factor in free text.
Does MGF work through the IGF-1 receptor?
The short peptide does not. In a receptor test spanning concentrations from 0.0625 to 1000 nanomoles per litre, neither the human MGF peptide nor the stabilised version produced any measurable activation. IGF-1 itself reached half its maximum in the same test at 0.86 nanomoles per litre. Whatever the peptide does, it does not do it through that receptor.
Is MGF the same molecule the body makes?
Usually not. The body's own Ec domain ends in the sequence GSTFEERK. The peptide found in research papers and in confiscated vials ends in GSTFEEHK, one building block different at position 23. Anti-doping chemists label the seized material MGF R23H for exactly that reason.
Is MGF banned in sport?
Yes, at all times, in and out of competition. Section S2.3 of the 2026 Prohibited List names mechano growth factors as their own entry, alongside IGF-1 rather than under it. It counts as a non-specified substance, the stricter of the two categories. The ban has stood since 2005.
Can laboratories detect MGF?
Yes, and they have been able to for over a decade. A black-market analogue was characterised in 2012, with a specific fragment transition that separates it from the body's own molecule. A product advertised as undetectable was characterised in 2014 and folded into routine testing down to 0.25 nanograms per millilitre.
What are the known side effects of MGF?
None are documented, because no person has ever been given it in a study. That is an empty file, not a clean one. The one signal that does exist points the wrong way: the Ec peptide appears repeatedly in cancer research as a growth and progression factor, and no cancer-risk study of any kind has been done.
Is MGF legal to buy?
No country has approved it as a medicine. German law names it in the annex to its anti-doping act and sets the criminal threshold at 3 milligrams, one of the lowest figures in the whole schedule. Australia captures it through a class entry that makes possession without authority an offence. A research-use-only label changes none of this.
What is the difference between MGF and PEG-MGF?
PEG-MGF is the same short peptide with a polymer chain attached, and it has its own page. Regulators treat them separately. PEG-MGF was put forward as a compounding ingredient in the United States, flagged for safety concerns and then withdrawn, while plain MGF sits in the category for ingredients nominated without adequate support. No half-life has ever been published for either.
Do the animal studies of MGF apply to people?
Not straightforwardly, and this peptide is an unusually clear case. When researchers made the human and the mouse version and tested each in the other species, both were inactive across the board. Several of the animal studies also delivered a gene construct or an implanted polymer rod rather than an injected peptide.
Sources
- ClinicalTrials.gov API v2. Three interventional queries run on 16 September 2026: "mechano growth factor" returns 105 records, none with MGF as the intervention; "MGF peptide" returns 43, likewise none; "IGF-1Ec" returns one, NCT07151807, an observational study of serum markers at Canakkale Onsekiz Mart University. https://clinicaltrials.gov
- Janssen JA, Hofland LJ, Strasburger CJ, van den Dungen ES, Thevis M (2016). Potency of full-length MGF to induce maximal activation of the IGF-I R is similar to recombinant human IGF-I at high equimolar concentrations. PLoS One 11(3):e0150453. PMID 26991004. DOI 10.1371/journal.pone.0150453. Full text retrieved 16 September 2026.
- Fornaro M, Hinken AC, Needle S, et al. (2014). 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 306(2):E150-E156. PMID 24253050. DOI 10.1152/ajpendo.00408.2013. Abstract retrieved 16 September 2026. Carried out at two pharmaceutical companies; peptide up to 500 ng/ml had no effect on myoblasts, primary human muscle cells, primary mouse muscle stem cells or ERK activation in cardiac myocytes.
- 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.
- UniProt. Entry P05019 (IGF1_HUMAN) and isoform P05019-4, 158 amino acids, C-terminus GSTFEERK. Retrieved 16 September 2026. https://www.uniprot.org/uniprotkb/P05019
- Matheny RW Jr, Nindl BC, Adamo ML (2010). Minireview: mechano-growth factor, a putative product of IGF-I gene expression involved in tissue repair and regeneration. Endocrinology 151(3):865-875. PMID 20130113. DOI 10.1210/en.2009-1217. Abstract retrieved 16 September 2026; full text not accessible.
- World Anti-Doping Agency. The 2026 Prohibited List, in force from 1 January 2026. Section S2.3, growth factors and growth factor modulators, page 8, entry "Mechano growth factors (MGFs)"; index page 8. Retrieved 16 September 2026.
- Dopingmittel-Mengen-Verordnung of 10 March 2023, BGBl. 2023 I No. 67, pages 5-10, annex section II.3: "Mechano Growth Factor (MGF) und MGF-Varianten - 3 mg". Retrieved from gesetze-im-internet.de on 16 September 2026.
- 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.
- Armakolas A, Kaparelou M, Dimakakos A, et al. (2015). Oncogenic role of the Ec peptide of the IGF-1Ec isoform in prostate cancer. Molecular Medicine 21(1):167-179. PMID 25569803. PMC4461578. DOI 10.2119/molmed.2014.00222.
- Yang S, Alnaqeeb M, Simpson H, Goldspink G (1996). Cloning and characterization of an IGF-1 isoform expressed in skeletal muscle subjected to stretch. Journal of Muscle Research and Cell Motility 17(4):487-495. PMID 8884603. DOI 10.1007/BF00123364.
- Zablocka B, Goldspink PH, Goldspink G, Gorecki DC (2012). Mechano-growth factor: an important cog or a loose screw in the repair machinery? Frontiers in Endocrinology 3:131. PMID 23125840. PMC3485521. DOI 10.3389/fendo.2012.00131. Full text retrieved 16 September 2026.
- Shioura K, Pena J, Goldspink P (2014). Administration of a synthetic peptide derived from the E-domain region of mechano-growth factor delays decompensation following myocardial infarction. International Journal of Cardiovascular Research 3(3):1000169. PMID 25606570. PMC4297642. DOI 10.4172/2324-8602.1000169.
- Papageorgiou E, Philippou A, Armakolas A, Christopoulos PF, Dimakakos A, Koutsilieris M (2016). The human Ec peptide: the active core of a progression growth factor with species-specific mode of action. Hormones (Athens) 15(3):423-434. PMID 27838607. DOI 10.14310/horm.2002.1699.
- Pena JR, Pinney JR, Ayala P, Desai TA, Goldspink PH (2015). Localized delivery of mechano-growth factor E-domain peptide via polymeric microstructures improves cardiac function following myocardial infarction. Biomaterials 46:26-34. PMID 25678113. PMC4328136. DOI 10.1016/j.biomaterials.2014.12.050. Full text retrieved 16 September 2026; carries the sequence YQPPSTNKNTKSQRRKGSTFEEHK.
- NCBI RefSeq. NP_001104753.1, insulin-like growth factor 1 isoform 1 preproprotein, Homo sapiens, 158 amino acids, C-terminus GSTFEERK. Retrieved 16 September 2026.
- Dominikowski A, Rekos Z, Olejarz M, Szczepanek-Parulska E, Domin R, Ruchala M (2026). The emerging landscape of performance-enhancing peptides modulating the GH-IGF1 axis. Frontiers in Endocrinology 17:1822475. PMID 42395176. PMC13322892. DOI 10.3389/fendo.2026.1822475. Grades PEG-MGF and IGF-1 LR3 at evidence level D and records that no half-life is reported.
- European Medicines Agency. Official medicines data export, medicines-output-medicines-report_en.xlsx, downloaded 16 September 2026. The string "mechano" returns no record; the control search "mecasermin" returns three, for Increlex, procedure EMEA/H/C/000704, ATC H01AC03.
- Drugs@FDA and openFDA label APIs, queried 16 September 2026. Active ingredient "MECHANO GROWTH FACTOR" returns NOT_FOUND in both; the control "MECASERMIN" returns BLA 021839 and three labels. DailyMed API v2 returns nothing for "mecha" and one record for the control "increlex".
- Health Canada Drug Product Database API, queried 16 September 2026. Active ingredient "mechano" returns an empty array, as does "growth factor"; the control "mecasermin" returns drug code 99902, INCRELEX, DIN 02509733. https://health-products.canada.ca/api/drug/
- PubChem PUG-REST. Name queries for "mechano growth factor", "MGF peptide" and "IGF-1Ec" each return PUGREST.NotFound, queried 16 September 2026. No CAS registry number or UNII could be established from a primary source for either form.
- Mavrommatis E, Shioura KM, Los T, Goldspink PH (2013). The E-domain region of mechano-growth factor inhibits cellular apoptosis and preserves cardiac function during myocardial infarction. Molecular and Cellular Biochemistry 381(1-2):69-83. PMID 23712705. DOI 10.1007/s11010-013-1689-4.
- Solis C, Thompson WC, Pena JR, et al. (2022). Mechano-growth factor E-domain modulates cardiac contractile function through 14-3-3 protein interactomes. Frontiers in Physiology 13:1028345. PMID 36467694. DOI 10.3389/fphys.2022.1028345.
- Kandalla PK, Goldspink G, Butler-Browne G, Mouly V (2011). 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 ages. Mechanisms of Ageing and Development 132(4):154-162. PMID 21354439. DOI 10.1016/j.mad.2011.02.007.
- Liu Y, Heinichen M, Wirth K, Schmidtbleicher D, Steinacker JM (2008). Response of growth and myogenic factors in human skeletal muscle to strength training. British Journal of Sports Medicine 42(12):989-993. PMID 18308879. DOI 10.1136/bjsm.2007.045518.
- Carpenter V, Matthews K, Devlin G, et al. (2008). Mechano-growth factor reduces loss of cardiac function in acute myocardial infarction. Heart, Lung and Circulation 17(1):33-39. PMID 17581790. DOI 10.1016/j.hlc.2007.04.013.
- Riddoch-Contreras J, Yang SY, Dick JR, Goldspink G, Orrell RW, Greensmith L (2009). Mechano-growth factor, an IGF-I splice variant, rescues motoneurons and improves muscle function in SOD1(G93A) mice. Experimental Neurology 215(2):281-289. PMID 19038252. DOI 10.1016/j.expneurol.2008.10.014.
- Quesada A, Micevych P, Handforth A (2009). C-terminal mechano growth factor protects dopamine neurons: a novel peptide that induces heme oxygenase-1. Experimental Neurology 220(2):255-266. PMID 19735655. DOI 10.1016/j.expneurol.2009.08.029.
- Zhang B, Luo Q, Kuang D, Ju Y, Song G (2016). Mechano-growth factor E peptide promotes healing of rat injured tendon. Biotechnology Letters 38(10):1817-1825. PMID 27334712. DOI 10.1007/s10529-016-2162-8.
- Sha Y, Cai W, Mohanad Khalid A, et al. (2021). Pretreatment with mechano growth factor E peptide attenuates osteoarthritis through improving cell proliferation and extracellular matrix synthesis in chondrocytes under severe hypoxia. International Immunopharmacology 97:107628. PMID 34015701. DOI 10.1016/j.intimp.2021.107628.
- Philippou A, Armakolas A, Panteleakou Z, et al. (2011). Insulin-like growth factor-1Ec (MGF) expression in eutopic and ectopic endometrium. Molecular Medicine 17(1-2):21-28. PMID 20844834.
- Kasprzak A, et al. (2020). Increased expression of IGF-1Ec with increasing colonic polyp dysplasia and colorectal cancer. Journal of Cancer Research and Clinical Oncology 146(11):2841-2855. PMID 32772171.
- Christopoulos PF, Philippou A, Koutsilieris M (2016). The role of the IGF-1 Ec in myoskeletal system and osteosarcoma pathophysiology. Critical Reviews in Oncology/Hematology 108:137-148. PMID 27931832.
- 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.
- Thevis M, Thomas A, Geyer H, Schanzer W (2014). Mass spectrometric characterization of a biotechnologically produced full-length mechano growth factor (MGF) relevant for doping controls. Growth Hormone and IGF Research 24(6):276-280. PMID 25466910. DOI 10.1016/j.ghir.2014.10.004. Records the monoisotopic mass of 12,264.9 daltons, the R109H substitution, a detection limit of 0.25 ng/ml, and prohibition in sport since 2005.
- U.S. Food and Drug Administration. Certain bulk drug substances for use in compounding that may present significant safety risks, page as of 22 April 2026, full text retrieved 16 September 2026. The only occurrence of "mechano" is "Mechano growth factor pegylated (PEG-MGF)" under bulk drug substances nominated but withdrawn; the agency states it has identified no human exposure data for it by any route.
- Goldspink G, Wessner B, Bachl N (2008). Growth factors, muscle function and doping. Current Opinion in Pharmacology 8(3):352-357. PMID 18353722. DOI 10.1016/j.coph.2008.02.002.
- McKoy G, Ashley W, Mander J, et al. (1999). Expression of insulin growth factor-1 splice variants and structural genes in rabbit skeletal muscle induced by stretch and stimulation. The Journal of Physiology 516(Pt 2):583-592. PMID 10087355. DOI 10.1111/j.1469-7793.1999.0583v.x.
- Hill M, Goldspink G (2003). Expression and splicing of the insulin-like growth factor gene in rodent muscle is associated with muscle satellite (stem) cell activation following local tissue damage. The Journal of Physiology 549(Pt 2):409-418. PMID 12692175. DOI 10.1113/jphysiol.2002.035832.
- Owino V, Yang SY, Goldspink G (2001). Age-related loss of skeletal muscle function and the inability to express the autocrine form of insulin-like growth factor-1 (MGF) in response to mechanical overload. FEBS Letters 505(2):259-263. PMID 11566187. DOI 10.1016/s0014-5793(01)02825-3.
- Iida K, Itoh E, Kim DS, et al. (2004). Muscle mechano growth factor is preferentially induced by growth hormone in growth hormone-deficient lit/lit mice. The Journal of Physiology 560(Pt 2):341-349. PMID 15308683. DOI 10.1113/jphysiol.2004.069500.
- U.S. Food and Drug Administration. Bulk drug substances nominated for use in compounding under section 503A of the Federal Food, Drug, and Cosmetic Act, list updated 14 May 2026, retrieved 16 September 2026. "Mechano growth factor (MGF)" is listed under 503A category 3, bulk drug substances nominated without adequate support. https://www.fda.gov/media/94155/download
- Annex to section 2 subsection 3 of the German Anti-Doping Act (AntiDopG), BGBl. 2023 I No. 67, pages 1-5, part II.3: "Mechano Growth Factor (MGF) und MGF-Varianten". Retrieved from gesetze-im-internet.de on 16 September 2026.
- Misuse of Drugs Act 1971, Schedule 2, Part III (Class C), retrieved 16 September 2026. Lists somatropin, somatrem and chorionic gonadotrophin among the peptide hormones; growth factors such as IGF-1 or MGF are not named. https://www.legislation.gov.uk/ukpga/1971/38/schedule/2
- Therapeutic Goods (Poisons Standard - June 2026) Instrument 2026, F2026L00633, registered 28 May 2026. Schedule 4 entries "INSULIN-LIKE GROWTH FACTOR I." and "INSULIN-LIKE GROWTH FACTORS except when separately specified in this Schedule"; Appendix D, clause 5, item 24. The names mechano growth factor and MGF do not appear in the instrument.
- Swiss Federal Department of Finance, Federal Office for Customs and Border Security, Swissmedic and Swiss Sport Integrity. Cross-agency campaign "Peptides 2026", operation of 22 June 2026, statement of 30 June 2026, retrieved 16 September 2026. 46 consignments checked, 23 held back, 21 classed as doping material. The Swiss Sport Integrity list for 2026 names "mechanisch induzierte Wachstumsfaktoren (MGF)" in section S2.3.
- Thomas A, Walpurgis K, Tretzel L, et al. (2015). Expanded test method for peptides above 2 kDa employing immunoaffinity purification and LC-HRMS/MS. Drug Testing and Analysis 7(11-12):990-998. PMID 26382721. DOI 10.1002/dta.1868.
- U.S. Food and Drug Administration. Warning letter to Gram Peptides, reference 721806, 31 March 2026, retrieved 16 September 2026. Cites products marketed for human use as unapproved new drugs under section 505(a) of the Federal Food, Drug, and Cosmetic Act. MGF itself is not named in this letter.
Cite this page
The facts on this page were checked on 16 September 2026, and every register search behind the status table was run on that date. Nobody is developing MGF as a medicine, so the anti-doping and legal entries are the parts most likely to change.
myPeptides Research & Editing. (2026). Mechano Growth Factor (MGF): what the studies show, status and safety. Version 1.0, 16 September 2026. myPeptides Peptide Register. Retrieved from https://mypep.app/peptides/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 any first human study, on any change in the compounding lists, or on any change in the anti-doping or Poisons Standard classification.