MGF (Mechano Growth Factor)
Also called IGF-1Ec; MGF E-peptide
A name tied to research on how the IGF-1 system responds to muscle loading. Studies of MGF inside exercising muscle are not studies of the synthetic peptide sold under that name, and lab results conflict.
Overview
What it is
IGF-1Ec is a splice variant of the IGF-1 gene; "MGF E-peptide" is a 24-amino-acid fragment from its end. PEG-MGF is a separately modified form.
How it works
The idea is that loading or injury raises local MGF, which activates muscle stem cells (satellite cells) for repair.
What the research shows
In a 2003 biopsy study, resistance exercise raised MGF-related RNA in younger but not older men; no one received MGF. A 2014 study could not reproduce MGF effects on muscle cells, including human cells. A later mouse-cell experiment reported different results.
Studied for
- Natural MGF response to exercisehuman biopsies
- Muscle stem cell activitylab, conflicting
Safety and regulatory status
Safety and side effects
No human treatment data. FDA notes no identified human exposure data for PEG-MGF and flags immune and impurity concerns.
Regulatory status
Not FDA approved. Prohibited at all times by WADA (S2.3).
Mixing and dosing reference
Reference information only. Read before using this section.
MGF (5 mg Vial) Dosage Protocol
- Vial
- 5 mg MGF
- Add diluent
- 3 mL
- Concentration
- 1.67 mg/mL
- 1 unit (U-100)
- 16.67 mcg in 0.01 mL
- Route
- Subcutaneous
- How often
- Once per day (subcutaneous).
- Typical range
- 100–300 mcg once daily (gradual titration).
- Cycle length
- 8–12 weeks; optional extension to 16 weeks.
Standard / Gradual Approach
| Week | Daily Dose (mcg) | Units (per injection) (mL) |
|---|---|---|
| Week 1 | 100 mcg (0.1 mg) | 6 units (0.06 mL) |
| Week 2 | 150 mcg (0.15 mg) | 9 units (0.09 mL) |
| Week 3 | 200 mcg (0.2 mg) | 12 units (0.12 mL) |
| Week 4 | 250 mcg (0.25 mg) | 15 units (0.15 mL) |
| Weeks 5–8 | 300 mcg (0.3 mg) | 18 units (0.18 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; follow the exact preparation’s validated use-by and sterile-handling instructions.
Dosing details
- Start: 100 mcg daily; increase by ~50 mcg weekly as tolerated.
- Target: 250–300 mcg daily by Weeks 4–8.
- Frequency: Once per day (subcutaneous).
- Cycle Length: 8–12 weeks; optional extension to 16 weeks.
- Timing: Any consistent time; rotate injection sites.
Storage
- Lyophilized: Store at −20 °C (−4 °F) or colder for long‑term; refrigerate at 4 °C (39.2 °F) for short‑term.
- Reconstituted: Refrigerate at 2–8 °C (35.6–46.4 °F); follow the exact preparation’s validated use-by and sterile-handling instructions; avoid freeze–thaw cycles.
- 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) by at least 1–1.5 inches from prior sites to avoid irritation.
- Use 23–25 gauge, 5/8‑inch needles for subcutaneous administration.
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.
- MGF has a short half‑life; PEGylated forms (PEG‑MGF) offer extended duration but follow different protocols.
Protocol source: PeptideDosages.com
Common questions
Is MGF the same as PEG-MGF?
No. PEG-MGF is chemically modified and needs its own evidence.
Does a study with human volunteers prove MGF works?
Not if they only measured natural levels after exercise.
Is MGF allowed in sport?
No.
Related in Performance and Recovery
Sources and further reading (5)
- Matheny RW Jr, et al. Mechano-growth factor: a putative product of IGF-I gene expression. Endocrinology, 2010.
- Hameed M, et al. IGF-I splice variants in young and old muscle after resistance exercise. J Physiol, 2003.
- Fornaro M, et al. MGF peptide has no apparent effect on myoblasts. Am J Physiol Endocrinol Metab, 2014.
- WADA. The Prohibited List, S2.3.
- Source summary: PeptideDosages.com research overview (rewritten for NVO).