MGF
Mechano growth factor, IGF-1Ec E-domain peptide
- Common dose
- No tested dose
- Cycle
- No set cycle
- Vial sizes
- Not established
A 24-amino-acid tail from IGF-1Ec, a form of IGF-1 that muscle makes after hard exercise or injury. The vials hold that tail on its own, which is not the same molecule as the natural splice variant.
Status
- Approval
- Not approved as a drug in the US or EU, and no company has applied.
- US compounding
- In FDA Category 3 for pharmacy compounding (503A) as of the May 14, 2026 list, meaning it was nominated without enough supporting information for FDA to evaluate it. That is not a safety finding, and it is not approved. The pegylated form, PEG-MGF, was handled separately.
- Sport (WADA 2026)
- Banned in sportS2.3 growth factors, which names “Mechano growth factors (MGFs)” outright. Banned at all times, in and out of competition.
Category 2 is FDA’s list of bulk substances that may present significant safety risks in compounding. The 503A bulks list adds substances that pharmacies may compound with. Advisory committee votes are advice; FDA makes the final decision. Sport status follows the WADA Prohibited List in force since January 1, 2026; athletes should confirm with their anti-doping organization. Checked October 5, 2026. Status of every compound.
How it works
MGF is the 24-amino-acid tail of IGF-1Ec, a form of IGF-1 that muscle makes after hard exercise or injury. A 2002 cell study reported the free tail made muscle cells multiply and held back their maturing, through some receptor other than the IGF-1 receptor. Two pharmaceutical companies found no such effect up to 500 ng/mL, and a later study found E-peptide effects need the IGF-1 receptor after all.
AnimalMainly from cell and animal studies; not shown in people.
Not known
No target is established, and the free peptide has never been isolated from any cell, fluid or tissue, so whether it occurs naturally is unclear. No person has received it in a published study.
Protocol
No dose has been tested in a person. Amounts quoted online differ several-fold between sources and trace back to cell and animal work, not to any human study.
- Frequency
- Not established
- Route
- Intramuscular or subcutaneous injection (community); no human study has given it by any route
- Cycle
- No established cycle.
No set cycle, shown over 26 weeks
Taking it
Where it goes
No human study has given it by any route. Community use is injection into muscle or under the skin, on the idea that it acts near the injection site; that has not been shown in a person.
If you miss a dose
No published guidance.
What to expect
- Any time
Nothing has been measured in a person: no effect on muscle, no time course, no dose response.
Community - In cell studies
The 2002 report found the E domain increased myoblast growth and delayed differentiation. In 2013, two pharmaceutical companies testing up to 500 ng/mL found no effect on human or mouse muscle cells, on primary mouse muscle stem cells, or on signaling in heart cells.
Animal - In animals
Separate reports describe nerve protection in gerbil brain ischemia and preserved heart function after induced heart attack in mice and sheep. None of this has been repeated in a person.
Animal
Side effects and what to do
Unknown: never given to a person in a published study
There is no measured side-effect profile. Treat anything new as unexplained and stop.
Cell-growth concern
The peptide is overexpressed in prostate cancer tissue and stimulated prostate cancer and osteosarcoma cell growth in culture. Any new or growing lump needs medical assessment.
Unknown immune reaction
FDA has flagged immunogenicity and peptide-impurity concerns for this class, and seized products carried a modified C-terminus. Stop for hives, swelling or wheeze.
Injection-site redness, swelling or pain
Expected with any injection. A site that is hot, spreading and painful needs medical care.
Hives with face or throat swelling, trouble breathing, or an injection site that is hot, spreading and painful: stop and get medical help. Have any new or growing lump assessed.
Who should avoid it
No product label covers MGF, so these come from human studies and from precautions based on how it works. Most important first.
- Anyone with active or past cancer
- PrecautionThe same peptide made human prostate cancer cells multiply and drove osteosarcoma cell growth, migration and invasion in culture, and the IGF-1Ec form is raised in prostate tumors.
- Anyone relying on product quality
- PrecautionProducts analyzed in 2012 were amidated versions, not the human sequence, and FDA flags immune reactions and peptide impurities for this class.
- Pregnancy or breastfeeding
- PrecautionNo human safety data exist, and no animal study has looked at effects on development or reproduction.
- People with diabetes or high blood sugar
- PrecautionLab work suggests its effects run through the IGF-1 receptor, which also carries insulin-like signals; no effect on blood sugar has been measured in people.
Interactions
Precaution: follows from how it works or from a related drug, and hasn’t been tested. This isn’t a complete list: a pharmacist or doctor can check a specific medicine or condition.
Tracking and pairing
Worth tracking
- Any new or growing lump
- Injection-site reactions
Often paired with
- BPC-157
A common community pairing for recovery. The combination has never been tested, in people or in animals.
Human studies
No published human studies of MGF turned up in our October 2026 review. The evidence note at the top of this page sums up what is known.
Limits of the evidence
No published study has given MGF to a person by any route. The central cell finding failed replication at two companies, and the free peptide has never been found in a cell, fluid or tissue. What remains is cell work plus small animal studies in muscle and brain. The amounts and the half-life quoted online rest on no human measurement.
How it’s supplied
Datasheet
- Half-life
- No reliable value has been published.
- Type
- Peptide, 24 amino acids
- Molecular weight
- about 2,868 g/mol (calculated; about 2,867 for the C-terminal amide form found in seized products)
- Formula
- C121H199N41O40
- Sequence
- YQPPSTNKNTKSQRRKGSTFEERKThe C-terminal E domain of human IGF-1Ec
- Storage before use
- Freezer (about −20 °C) for long-term storage, kept dry.
- After mixing or opening
- Fridge (2–8 °C); use within about 4 weeks.
- Molecule: Sequence: the C-terminal 24 residues of human IGF-1 isoform 4 (UniProt P05019-4). Formula and weight computed from that sequence and cross-checked with ExPASy ProtParam. No PubChem record exists for the free E-domain peptide. Esposito et al. 2012 found C-terminally amidated analogues in black-market products.
- Storage: Community Common practice; no approved label exists for this peptide
Every compound side by side: the half-life chart and the storage chart.
Cautions
- What is sold is the 24-amino-acid tail alone. The natural splice variant is a whole pro-IGF-1 protein, and the free tail has never been found in a cell, a body fluid or a tissue.
- Products analyzed in 2012 were C-terminally amidated versions, not the human sequence.
- The central claim failed replication: two pharmaceutical companies found no effect on muscle-cell growth or differentiation at up to 500 ng/mL.
- The same peptide stimulated growth of human prostate cancer cells, and promoted growth, migration and invasion of osteosarcoma cells, in culture.
- The “5 to 7 minute half-life” quoted online has no published measurement behind it.
Questions
What is MGF?
A 24-amino-acid tail from IGF-1Ec, a form of IGF-1 that muscle makes after hard exercise or injury. The vials hold that tail on its own, which is not the same molecule as the natural splice variant.
How does MGF work?
MGF is the 24-amino-acid tail of IGF-1Ec, a form of IGF-1 that muscle makes after hard exercise or injury. A 2002 cell study reported the free tail made muscle cells multiply and held back their maturing, through some receptor other than the IGF-1 receptor. Two pharmaceutical companies found no such effect up to 500 ng/mL, and a later study found E-peptide effects need the IGF-1 receptor after all. No target is established, and the free peptide has never been isolated from any cell, fluid or tissue, so whether it occurs naturally is unclear. No person has received it in a published study.
Is MGF FDA-approved?
Not approved as a drug in the US or EU, and no company has applied. In FDA Category 3 for pharmacy compounding (503A) as of the May 14, 2026 list, meaning it was nominated without enough supporting information for FDA to evaluate it. That is not a safety finding, and it is not approved. The pegylated form, PEG-MGF, was handled separately.
What is the usual MGF dose?
From community reports, not established: No dose has been tested in a person. Amounts quoted online differ several-fold between sources and trace back to cell and animal work, not to any human study. These are the amounts sources reference, not recommendations.
Who should avoid MGF?
No product label covers MGF, so these come from human studies and from precautions based on how it works. Anyone with active or past cancer: The same peptide made human prostate cancer cells multiply and drove osteosarcoma cell growth, migration and invasion in culture, and the IGF-1Ec form is raised in prostate tumors. Anyone relying on product quality: Products analyzed in 2012 were amidated versions, not the human sequence, and FDA flags immune reactions and peptide impurities for this class. Pregnancy or breastfeeding: No human safety data exist, and no animal study has looked at effects on development or reproduction. The “Who should avoid it” section lists 1 more group.
How should MGF be stored?
Before mixing: Freezer (about −20 °C) for long-term storage, kept dry. After mixing: Fridge (2–8 °C); use within about 4 weeks. This is common practice; no product label covers it.
Is MGF banned in sport?
Yes. S2.3 growth factors, which names “Mechano growth factors (MGFs)” outright. Banned at all times, in and out of competition.
Has MGF been studied in people?
No published human studies turned up in our October 2026 review. The evidence note at the top of this page sums up what is known.
Sources
- Fornaro et al., mechano-growth factor peptide has no apparent effect on myoblasts or primary muscle stem cells (Am J Physiol Endocrinol Metab 2014) PMID 24253050
- Matheny, Nindl and Adamo, minireview: mechano-growth factor, a putative product of IGF-I gene expression (Endocrinology 2010) PMID 20130113
- Yang and Goldspink, different roles of the IGF-I Ec peptide (MGF) and mature IGF-I in myoblast proliferation and differentiation (FEBS Lett 2002) PMID 12095637
- Esposito, Deventer and Van Eenoo, a C-terminal amidated MGF analogue in black market products (Rapid Commun Mass Spectrom 2012) PMID 22328223
- Armakolas et al., MGF E peptide activity in human prostate cancer cells (Prostate 2010) PMID 20564425
For the protocol details
- Brisson and Barton, IGF-I E-peptide activity is dependent on the IGF-I receptor (PLoS One 2012) PMID 23029120
- Kandalla et al., MGF E peptide activates human muscle progenitor cells (Mech Ageing Dev 2011) PMID 21354439
- Dłużniewska et al., neuroprotective effect of the C-terminal peptide of IGF-1 Ec in brain ischemia (FASEB J 2005) PMID 16144956
For how it works, who should avoid it and the limits of the evidence
- Shang, Fan and Liu, MGF E peptide and osteosarcoma cell growth, migration and invasion (Oncol Lett 2015) PMID 26622556
Doses tagged Community come from public dosing guides and user reports, checked against at least two of them. Those sites aren’t named here because many of them sell peptides or earn commissions on them.