PEG-MGF
Pegylated mechano growth factorIGF-1EcMGFEvidence
Preclinical
Typical vial
2 mg
Route
2 routes
Status
United States
What it is
A splice variant of IGF-1 released by damaged muscle, pegylated to last longer. No human trials, and the same proliferation concern as everything in the IGF family.
Mechano growth factor is a splice variant of IGF-1 that muscle produces after mechanical damage. Its proposed role is local: activating satellite cells, the muscle stem cells that fuse into damaged fibres during repair. The natural version acts and is gone within minutes.
PEG-MGF attaches polyethylene glycol to that peptide, which slows clearance dramatically. It is the same trick used across biologics to turn a short-acting molecule into a long-acting one.
The engineering also removes what made the natural molecule interesting. MGF is released locally, briefly, where damage occurred. A pegylated version circulating for days is not a longer version of that signal; it is a different thing, and nothing establishes what it does. There has never been a human trial.
How it works
MGF is produced when muscle is mechanically loaded or damaged, and activates satellite cells to proliferate and fuse into existing fibres. That is a real and well-described part of how muscle repairs itself.
Pegylation attaches a polymer chain that shields the peptide from clearance, extending its presence from minutes to days.
The natural signal is local and transient by design. Sustained systemic exposure to a satellite cell activator is not something the body does, and no study has examined what it produces.
MGF derives from IGF-1 by alternative splicing, so it shares the family's proliferative signalling, and the concerns that come with it.
What it is studied for
Each entry states the evidence behind it. We do not rank indications by effectiveness — for most compounds here, that would be a claim nobody can support.
Muscle repair and growth
Community practiceThe reason it is bought.
EvidenceAnimal and cell studies show satellite cell activation. No human trial of PEG-MGF has ever been conducted.
Regulatory status
Last reviewed 18 Aug 2026. Positions in this category change frequently, so we date the line.
Not approved anywhere and never studied in a human trial. Sold only as a research chemical. Prohibited in sport as a growth factor.
Identity and clearance
What the molecule is, and how long a dose stays measurable.
Molecule
- Class
- Pegylated C-terminal peptide of the IGF-1Ec splice variant
- Length
- 24 amino acids
The PEG chain is a substantial fraction of the molecule's mass, and exists solely to slow clearance.
Dose protocols reported in sources
Displayed for reference only. Every row says where it came from, and a trial protocol and a community convention are not the same kind of information. None of this is fed into the calculator, and none of it is a recommendation.
A week-by-week progression is also reported for PEG-MGF. See it against a 2 mg vial, where the syringe units can be worked out.
| Goal | Dose | Frequency | Route | Units, 2 mg vial | Source | Start this protocol |
|---|---|---|---|---|---|---|
| Commonly described community protocol | 200 mcg – 500 mcg | Twice weekly, often on non-training days | SubcutaneousNo trial supports any of this. Local injection into a trained muscle is often described, on the theory that MGF is a local signal. Pegylating it is precisely what undoes that. | 10–25 u | Community practice | Start this |
Start this copies a row into a protocol of your own, which you can then edit. Where a source gave a dose range or an ambiguous frequency, those fields arrive empty — we will not pick a number on your behalf.
CheckRows marked community practice describe what people commonly do, drawn from public discussion. They are not derived from any trial and are not evidence that a dose is safe or effective.
Work out what to draw
Pre-filled with a 5 mg vial as a worked example. These are not recommended values — change them to match the vial in front of you.
Draw to 12 units on a 1 mL U-100 syringe. That is 0.12 mL, containing 300 mcg of PEG-MGF.
12 units sits exactly on a printed line.
BioAlmanac performs arithmetic on values you enter. It does not recommend doses, schedules or compounds, and nothing here is medical advice. Confirm every calculation against your vial and syringe before drawing, and speak with a licensed healthcare provider.
Open this calculation in the full calculator
Units, concentration, bacteriostatic water — the glossary defines the vocabulary, and a unit is not a fixed volume.
Safety
Reported effects, the situations that need care, and the ones that mean stop.
Reported effects
- EverythingCommunity practice
Unknown
No human study exists at any dose.
- Injection site reactionsCommunity practice
Commonly reported
- Unquantified proliferative riskCommunity practice
Mechanistically expected
This is an IGF-1 splice variant engineered to persist. IGF signalling drives cell proliferation, and sustained systemic exposure is exactly the scenario nobody has studied.
When to stop
- Any new lump, unexplained weight loss or unexplained persistent pain.
- Any allergic response: rash, hives, facial swelling or difficulty breathing. Seek urgent care.
- An injection site that becomes hot, spreading or produces pus.
Interactions and situations that need care
- Active or previous cancerAvoid
An IGF-1 splice variant engineered for sustained exposure is a proliferative signal with the clearance mechanism deliberately removed. No evidence supports that in someone with malignancy and the mechanism is a clear concern.
- Competing in a tested sportAvoid
Growth factors affecting muscle are named explicitly in WADA's S2 category and prohibited at all times.
- Pregnancy and breastfeedingAvoid
No safety data, for a growth factor variant whose signalling is central to development.
- Expecting local injection to keep it localUse caution
The PEG chain exists specifically to make the molecule persist and circulate. Injecting it into one muscle does not confine an effect that has been engineered to be systemic.
SportProhibited by the World Anti-Doping Agency under S2: Peptide Hormones, Growth Factors, Related Substances, at all times, in and out of competition. Growth factors affecting muscle are named explicitly in S2.
What to expect
What the sources describe over time, and how confident anyone can be about it.
HonestlyThere is no human efficacy data for this compound, so there is no evidence-based timeline to give. Any site publishing a week-by-week schedule of expected effects has invented it.
- No human trial of PEG-MGF exists.
- The natural molecule is a local, minutes-long signal. Pegylating it produces something systemic that lasts days. A different thing, not a better version.
- Local injection to grow a specific muscle has no human evidence and is inconsistent with what pegylation is for.
- It is an IGF-1 variant, so it carries the family's unquantified proliferative concern.
- Prohibited in sport at all times.
Storage and combinations
How to keep it, and what it does and does not go with.
Storage and handling
- Freeze-dried powder
- Refrigerated at 2–8 °C, protected from light.
- After mixing
- Refrigerated at 2–8 °C. Do not freeze once mixed.
- Long-term, frozen
- Unopened powder is stable at −20 °C or colder.
With other peptides
- IGF-1 LR3caution
Both are IGF-1 derivatives engineered to escape normal clearance. Running them together compounds the same proliferative signalling from two directions, with no human data on either.
Checking your vial
Research chemicals carry no manufacturing standard, so what the vial looks like is often the only quality signal available before you use it.
White cake, clear solution
Standard for a lyophilised peptide.
Collapsed cake or cloudy solution
Heat damage or degradation. Do not use it.
Vocabulary on this page
- Injection site
- Where on the body an injection is given. Rotating between sites is standard practice for anything given repeatedly.
- Peptide
- A short chain of amino acids: the same building blocks as a protein, in a chain short enough to behave differently.
- Protocol
- One compound, with a dose, a frequency and a length: the plan, as opposed to what was actually taken.
Questions
- What does the PEG do?
- It slows clearance, turning a molecule that lasts minutes into one that lasts days. It also removes the local, transient character that made MGF interesting in the first place.
- Does injecting it into a muscle grow that muscle?
- No human data supports it, and the pegylation argues against it, since the PEG chain exists to make the molecule systemic.
References
Everything on this page that came from a source, with the source.
Commonly reported community protocols
BioAlmanac editorial summary of public community sources, 2026 · Not a study
Records dose and route patterns described in public discussion. Carries no evidential weight about safety or effect.
Compiled community protocols
BioAlmanac editorial summary of a public protocol compilation, 2026 · Not a study
Records a week-by-week progression described on a vendor-adjacent protocol site, retrieved August 2026. Only the doses are taken from it. Its own syringe-unit conversions were checked against the vial sizes it states and several understate the volume by half, so nothing computed by that source is reproduced here — the units on this site are worked out from the vial in front of you. Carries no evidential weight about safety or effect.
PEG-MGF compared with
Also compared with Ipamorelin, CJC-1295, Tesamorelin, MK-677, GHRP-2, GHRP-6.
Related compounds
IGF-1 LR3
A modified insulin-like growth factor engineered to last far longer in the body than the natural hormone. It can cause hypoglycaemia, which makes it the most acutely dangerous compound on this site.
Ipamorelin
A selective growth hormone secretagogue that prompts a short pulse of GH release. Widely used, and supported almost entirely by early pharmacology rather than outcome trials.
CJC-1295
A GHRH analogue that raises growth hormone by amplifying the body's own release signal. Sold in two forms whose durations differ by two orders of magnitude.
Tesamorelin
A GHRH analogue approved by the FDA for reducing excess visceral fat in HIV-associated lipodystrophy. The only compound in this category with completed phase 3 trials.
Next
What to do with PEG-MGF
- Keep a record of itTurn a dose and a schedule into a protocol, then log what you actually take. PEG-MGF is filled in for you.
- See what it costsPer-milligram prices read from vendor sites and confirmed by a person, so vial sizes compare.
- Check a combinationWhat our profiles record about PEG-MGF alongside each other compound — including the pairs where nothing is recorded.
Keep this page honest
If something here is wrong, out of date, or missing a source, tell us and we will fix it and say that we did.
This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on BioAlmanac is medical advice. No clinician reviews these pages.
Page last updated 18 Aug 2026