PEG-MGF
Also called Pegylated mechano growth factor
A pegylated version of mechano growth factor peptide, discussed in muscle-repair research. Results are mixed even in the lab, and the FDA reports no identified human exposure data.
Overview
What it is
"MGF" can mean an IGF-1 splice variant or a short synthetic peptide from part of it (the E-domain). PEG (polyethylene glycol) is attached to change stability and how long it circulates.
How it works
The proposed idea is that MGF activates muscle stem cells (satellite cells) after strain or injury. PEGylation is meant to make it last longer but does not by itself prove better results.
What the research shows
A 2011 lab study using muscle cells from donors of different ages reported effects on satellite-cell growth and fusion. A 2014 study by pharmaceutical researchers tried to reproduce MGF effects and found none in several muscle-cell systems, including human cells, while mature IGF-1 did produce responses.
Studied for
- Muscle stem cell activitylab, conflicting results
- Heart function after injurymouse, related peptide
Safety and regulatory status
Safety and side effects
The FDA says it has not identified human exposure data for PEG-MGF by any route and flags possible immune reactions, impurities and difficulty characterizing the active ingredient. No predictable side-effect list exists.
Regulatory status
Not FDA approved; on FDA's list of compounding substances with significant safety concerns. Prohibited at all times by WADA.
Mixing and dosing reference
Reference information only. Read before using this section.
PEG MGF (2 mg Vial) Dosage Protocol
- Vial
- 2 mg PEG MGF
- Add diluent
- 3 mL
- Concentration
- 0.67 mg/mL
- 1 unit (U-100)
- 6.67 mcg in 0.01 mL
- Route
- Subcutaneous
- How often
- Once per day (subcutaneous).
- Typical range
- 200–500 mcg once daily (gradual titration over 8 weeks).
- Cycle length
- 8 weeks; optional extension to 12–16 weeks.
Standard / Gradual Approach
| Week | Daily Dose (mcg) | Units (per injection) (mL) |
|---|---|---|
| Weeks 1–2 | 200 mcg | 30 units (0.30 mL) |
| Weeks 3–4 | 300 mcg | 45 units (0.45 mL) |
| Weeks 5–6 | 400 mcg | 60 units (0.60 mL) |
| Weeks 7–8 | 500 mcg | 75 units (0.75 mL) |
How to mix
- Draw 3.0 mL bacteriostatic water with a sterile syringe.
- Inject slowly down the vial wall; avoid foaming.
- Gently swirl/roll until dissolved (do not shake).
- Label and refrigerate at 2–8 °C (35.6–46.4 °F), protected from light.
Dosing details
- Start: 200 mcg daily; increase by ~100 mcg every 2 weeks as tolerated.
- Target: 400–500 mcg daily by Weeks 5–8.
- Frequency: Once per day (subcutaneous).
- Cycle Length: 8 weeks; optional extension to 12–16 weeks.
- Timing: Any consistent time; rotate injection sites.
Storage
- Lyophilized: Store at −20 °C (−4 °F) in dry, dark conditions; minimize moisture exposure.
- Reconstituted: Refrigerate at 2–8 °C (35.6–46.4 °F); prepare aliquots if needed and avoid freeze–thaw.
- Allow vials to reach room temperature before opening to reduce condensation uptake.
Administration technique
- Clean the vial stopper and skin with alcohol; allow to dry.
- Pinch a skinfold; insert the needle at 45–90° into subcutaneous tissue.
- Do not aspirate for subcutaneous injections; inject slowly and steadily.
- Rotate sites systematically (abdomen, thighs, upper arms) to avoid lipohypertrophy and tissue irritation.
- Always use a new sterile needle and syringe for each injection; dispose of sharps in proper containers.
Important notes
- Use new sterile insulin syringes; dispose in a sharps container.
- Rotate injection sites (abdomen, thighs, upper arms) to reduce local irritation.
- Inject slowly; wait a few seconds before withdrawing the needle.
- Document daily dose and site rotation to maintain consistency.
- No clinical trials of PEG MGF have been completed; effects have been demonstrated in animal and cell models only.
Protocol source: PeptideDosages.com
Common questions
Is PEG-MGF the same as IGF-1?
No. It relates to IGF-1 biology but is a different molecule.
Is PEG-MGF better than MGF?
Clinical superiority has not been shown.
Is it allowed in sport?
No. Mechano growth factors are banned at all times.
Related in Performance and Recovery
Sources and further reading (5)
- FDA. Compounding substances that may present significant safety risks, PEG-MGF entry (checked Oct 2026).
- Kandalla PK, et al. MGF E-peptide effects on human muscle progenitor cells of different ages. Mech Ageing Dev, 2011.
- Fornaro M, et al. MGF peptide has no apparent effect on myoblasts or primary muscle stem cells. Am J Physiol Endocrinol Metab, 2014.
- WADA. The Prohibited List, S2.3.
- Source summary: PeptideDosages.com research overview (rewritten for NVO).