PEG-MGF dosage and protocol
Last reviewed Oct 7, 2026. Editorial policy
US regulatory status: Off Category 2, review pending
PEGylated Mechano Growth Factor is a splice variant of IGF-1 that promotes satellite cell activation for muscle repair and hypertrophy. The PEGylation extends its half-life significantly compared to standard MGF. Best used post-exercise to stimulate local muscle repair and new fiber activation.
- Vial size: 2 mg
- Reconstitution: 3 mL bacteriostatic water
- Concentration: 0.667 mg/mL
- Administration: subcutaneous
Research areas
- Muscle Growth
- Recovery
- Hypertrophy
- Tissue Repair
Quick start
- Reconstitute: Add 3.0 mL bacteriostatic water to the 2 mg vial for about 0.667 mg/mL
- Typical dose: 200 mcg daily rising to 500 mcg daily over 8 weeks
- Easy measuring: At 0.667 mg/mL, 1 unit = 0.01 mL = 6.67 mcg on a U-100 syringe; 200 mcg is 30 units and 500 mcg is 75 units
- Storage: Lyophilized at -20°C; refrigerate after mixing and use within 30 days
Dosing protocol
| Phase | Dose | Frequency | Volume |
|---|---|---|---|
| Weeks 1–2 | 200 mcg | Once daily (SC) | 0.30 mL (30 units) |
| Weeks 3–4 | 300 mcg | Once daily (SC) | 0.45 mL (45 units) |
| Weeks 5–6 | 400 mcg | Once daily (SC) | 0.60 mL (60 units) |
| Weeks 7–8 | 500 mcg | Once daily (SC) | 0.75 mL (75 units) |
How it works
Mechano growth factor (MGF) is a splice variant of the IGF-1 gene (IGF-1Ec in humans) that is expressed in muscle after mechanical loading or damage. Its distinctive E-domain peptide has been reported to activate muscle satellite cells, the stem cells that fuse into damaged fibres and drive repair, and to act partly independently of the classic IGF-1 receptor. Native MGF is degraded within minutes, so PEG-MGF attaches polyethylene glycol to extend its half-life and allow systemic dosing. Evidence is largely preclinical. In cell culture and rodent studies, MGF or its E-peptide increased satellite cell proliferation, and in some studies improved muscle regeneration after injury and protected heart or nerve tissue in injury models. Other laboratories have reported weaker or inconsistent effects, and whether the E-peptide has a distinct receptor remains debated. No controlled human trials of PEG-MGF exist. Claims of hypertrophy or faster recovery in people are based on extrapolation from animal work and anecdote. PEG-MGF is listed among prohibited substances in sport by WADA as a growth factor.
Units chart for a 2 mg vial
| Water added | Strength | 1 unit = | 200 mcg | 300 mcg | 400 mcg | 500 mcg |
|---|---|---|---|---|---|---|
| 1 mL | 2 mg/mL | 20 mcg | 10 units | 15 units | 20 units | 25 units |
| 2 mL | 1 mg/mL | 10 mcg | 20 units | 30 units | 40 units | 50 units |
| 3 mL | 0.67 mg/mL | 6.7 mcg | 30 units | 45 units | 60 units | 75 units |
Units on a U-100 insulin syringe (100 units = 1 mL).
Pages for each vial size and water volume
Reconstitution steps
- 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, protected from light
Storage
Evidence: Common practice. What vendors and users usually do. No published stability testing supports a specific number.
- Powder or unopened: Sealed powder: freezer (about −20 °C) for long-term storage, refrigerator for weeks. Let the vial reach room temperature before opening.
- Mixed or in use: Refrigerator, 2–8 °C. Do not freeze and thaw repeatedly.
- Use within: no tested number
- Light: Keep it in the box or another dark container.
Most reconstituted peptides are kept in the refrigerator (2–8 °C) and used within about 28 days. That is a convention, not tested data: the 28 days comes from the USP <797> limit for opened multiple-dose containers, which is about sterility, not about whether the peptide stays intact.
Sources: Crestigen: Peptide storage and handling guide; USP General Chapter <797> Pharmaceutical Compounding: Sterile Preparations
Store lyophilized at -20°C. Refrigerate after reconstitution, use within 30 days.
Important notes
- Research use only
- PEGylation extends half-life to ~days vs minutes for unPEGylated MGF
- Inject locally into trained muscle for best results
- Activates satellite cells for muscle fiber repair and growth
Supplies
- Bacteriostatic water
- Insulin syringes
- Alcohol swabs