Compounds / MGF
MGF
Also known as: Mechano Growth Factor; IGF-1Ec; MGF E-domain peptide; IGF-1 Ec splice variant; PEG-MGF (pegylated form)
Primary research focus: Muscle repair and satellite-cell research (IGF-1 splice variant E-domain peptide)
Last updated July 2026 · Reviewed against FDA labeling and published research.
What is MGF?
MGF (Mechano Growth Factor) is the E-domain peptide of IGF-1Ec, a splice variant of the IGF-1 gene that is transiently expressed in skeletal muscle, heart, and bone in response to mechanical loading or tissue damage. The synthetic research compound is the 24-amino-acid E-domain fragment, which appears to have biological activity independent of the mature IGF-1 portion. Because native MGF is degraded within minutes, a pegylated version (PEG-MGF) was created to extend its activity. It is a research compound with no approved human use and is prohibited in sport.
The IGF-1 gene undergoes alternative splicing to produce several isoforms; IGF-1Ea is the predominant circulating, liver-derived form, while IGF-1Ec (MGF) is the locally expressed, mechano-responsive form. Work from Geoffrey Goldspink's laboratory established a two-phase model: mechanical stress rapidly induces MGF expression, and the MGF E-peptide activates quiescent satellite (muscle stem) cells and drives myoblast proliferation, after which a shift to IGF-1Ea expression promotes differentiation and fusion, with mature IGF-1 driving hypertrophy through IGF-1R/PI3K/Akt/mTOR signaling. Notably, the E-peptide's effects appear to be independent of the IGF-1 receptor, and a specific MGF receptor has not been definitively identified.
How it’s supplied
Not an FDA-approved or commercially manufactured medicine. It is sold as a research-grade lyophilized peptide for reconstitution, both as the native 24-amino-acid E-domain peptide and as PEG-MGF. Research-grade products are not manufactured under pharmaceutical GMP conditions and are not FDA-reviewed for potency or sterility.
Dosage Chart
Units shown are for a U-100 insulin syringe (100 units = 1 mL), calculated from the vial size and BAC water you select. Always confirm against your prescription and your syringe markings.
| Phase | Dose | Frequency | Notes |
|---|---|---|---|
| Weeks 1-2 | 100mcg | 1x Daily | — |
| Weeks 3-4 | 200mcg | 1x Daily | — |
| Weeks 5-8 | 300mcg | 1x Daily | — |
- Rotate injection sites to reduce irritation and lipohypertrophy
- Not for use during pregnancy or breastfeeding
- Do not exceed the recommended dose to try to speed results
Potential Benefits and Side Effects
Effects reported in published research. Not a promise of results, and not medical advice.
- Reported in preclinical (cell and animal) research only; human efficacy is not established.
- Activation of quiescent satellite (muscle stem) cells and stimulation of myoblast proliferation.
- Reported role in the early phase of muscle repair after mechanical stress or damage.
- Reported cardioprotective effects in a mouse myocardial infarction model.
- Reported promotion of neurogenesis in the aging mouse brain.
- No human adverse-effect data are available.
- Theoretical concerns follow from growth-factor biology, including promotion of existing malignancy (IGF-1Ec has been reported in some prostate cancer tissue).
- Human tolerability and long-term safety are entirely uncharacterized.
- Research-grade material carries identity and purity risks.
Warnings and contraindications
Important safety information. This is not exhaustive — read the full prescribing information and consult your prescriber or pharmacist.
- No FDA-approved labeling exists; the following reflect the compound's status and the limits of its evidence, not established label warnings.
- There are no human clinical trials of MGF or PEG-MGF; human safety and efficacy are not established.
- IGF-1Ec has been reported in some prostate cancer tissue, raising a theoretical concern about promoting existing malignancy.
- For PEG-MGF specifically, the PEGylation site and its effect on biological activity have not been fully characterized, and no peer-reviewed study directly compares it with native MGF.
- MGF and its analogs are prohibited at all times in sport under the WADA Prohibited List (S2).
- Research-grade material varies in identity and purity; safety in pregnancy and breastfeeding has not been studied.
- Not established; no FDA-approved labeling. Precautionary considerations include active or suspected malignancy (particularly given reported IGF-1Ec expression in some prostate cancer tissue) and known hypersensitivity.
Reconstitution Steps
How to prepare the lyophilized vial. Confirm specifics with your pharmacist or prescriber.
- Confirm the amount of peptide in the vial and the volume of diluent you intend to use before starting.
- Wash your hands and gather supplies: the lyophilized vial, the diluent (typically bacteriostatic water), an alcohol swab, and a sterile syringe.
- Let the vial and diluent reach room temperature if they were refrigerated or frozen.
- Wipe the rubber stopper of both the peptide vial and the diluent vial with a fresh alcohol swab and let them air dry.
- Draw the intended diluent volume into the syringe.
- Insert the needle into the vial and slowly release the diluent down the inside wall rather than directly onto the powder, to avoid foaming.
- Do not shake. Gently swirl or roll the vial until fully dissolved.
- Inspect the solution: it should be clear and colorless with no visible particles. Do not use if cloudy or containing particles.
- Note the resulting concentration (amount divided by diluent volume) so it matches the reconstitution calculator on this page.
- Label the vial with the reconstitution date and store as directed under reconstituted storage.
US regulatory status
Classifications are public record but can change. For reference only, not legal advice.
Development: MGF was identified and characterized by Geoffrey Goldspink and colleagues at University College London beginning in the mid-1990s; McKoy and colleagues (Journal of Physiology, 1999) showed the splice variant rises sharply with mechanical load in stimulated rabbit muscle, giving the compound its name. Yang and Goldspink (FEBS Letters, 2002) established the functional division of labor between the MGF E-peptide (satellite cell activation and myoblast proliferation) and mature IGF-1 (differentiation and fusion). Additional preclinical work covers cardiac protection after myocardial infarction and neurogenesis in aging mouse brain. Both MGF and PEG-MGF have been characterized almost exclusively in preclinical and cell-culture systems; no human clinical trials have been conducted, and PEG-MGF in particular has a limited and largely indirect evidence base.
Notes: MGF is not FDA-approved for any human use and is sold as a research chemical, outside FDA quality oversight. Growth-factor peptides including PEG-MGF were placed on the FDA Category 2 bulk drug substances list, restricting compounding, and MGF-class compounds are expected to remain restricted rather than return to Category 1 in the 2026 reclassification; verify against the current FDA list. MGF and its analogs are prohibited at all times in sport under the WADA Prohibited List (category S2). It is not a controlled substance. (Status current as of mid-2026.)
International status
Pharmacokinetics
Storage and handling
Important Notes
Practical considerations for consistency and safety.
- MGF is the E-domain peptide of the IGF-1Ec splice variant, not IGF-1 itself, and it is structurally distinct from IGF-1 LR3.
- Native MGF has a half-life of only about 5 to 7 minutes, which is why PEG-MGF exists; but PEG-MGF's characterization is limited and vendor half-life claims are not backed by published human data.
- No human clinical trials have been conducted for either form.
- A specific MGF receptor has not been definitively identified.
- It is banned in sport (WADA S2), and IGF-1Ec expression in some prostate cancer tissue makes a cancer history a serious concern.
Lifestyle Factors
- Its biology is tied to mechanical loading: native MGF expression is triggered by resistance exercise and muscle damage.
- Human lifestyle interactions for the exogenous peptide are not characterized.
References
Related compounds
Important disclaimer
This page is an educational reference, not medical advice, a diagnosis, or a treatment recommendation, and not a substitute for your prescriber or pharmacist. Approval and regulatory status varies by compound and can change. Always confirm against current prescribing information and consult a qualified healthcare professional before making any decision about a medication.