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MGF

IGF-1 Splice Variant / Local Muscle Repair

Also known as: Mechano Growth Factor · IGF-1Ec

A splice variant of IGF-1 produced locally by muscle tissue in response to mechanical stress. Activates satellite cells & promotes local muscle repair & hypertrophy.

Typical Dose

100–200 mcg post-workout

Route

Intramuscular injection (target muscle group)

Cycle

4–8 weeks

Half-life

~15 minutes (native); use immediately post-reconstitution

Storage

Reconstituted: 2–8°C, use within 14–21 days.

Overview

Mechano Growth Factor (MGF) is a splice variant of the IGF-1 gene that is produced locally in muscle, bone, & tendon in response to mechanical stimulation & damage. Unlike systemic IGF-1, MGF acts as a local autocrine/paracrine factor — it does not circulate but activates muscle satellite cells (muscle stem cells) at the site of injury or loading.

The E domain of MGF (the C-terminal peptide unique to this splice variant) is the active domain. Synthetic MGF peptide replicates this E-domain fragment for injection. It is used to promote satellite cell proliferation, muscle repair, & — in performance contexts — to increase the number of myonuclei available for hypertrophy.

Quick Start Guide

1

Reconstitute with 2 mL bacteriostatic water per 2 mg vial.

2

Inject 200 mcg IM into trained muscle group immediately post-workout (within 30 min).

3

Timing is critical: MGF receptor expression peaks in the acute post-workout window.

Research Indications

Satellite cell activation (muscle stem cell)

Effective

Directly activates satellite cells to proliferate & fuse with existing muscle fibers, increasing myonuclei count.

Local muscle repair post-injury

Effective

Produced endogenously at injury sites; exogenous administration augments the natural repair signal.

Research Protocols

Post-workout satellite cell activation

4–8 weeks

Dose

200 mcg IM

Frequency

Immediately post-workout, training days only

Route

IM into trained muscle

Peptide Interactions

PEG-MGFCompatible

PEG-MGF is the longer-acting version; some users use native MGF post-workout & PEG-MGF on rest days.

IGF-1 LR3Compatible

Mechanistically complementary: MGF activates satellite cells; IGF-1 LR3 drives protein synthesis. Sometimes stacked.

Side Effects & Safety

Common

  • Injection site soreness (IM injection)
  • Muscle swelling at injection site

Uncommon

  • Hypoglycemia (much less than IGF-1 LR3 due to minimal insulin-receptor cross-activity)

When to Stop

  • Known malignancy
  • Signs of allergic reaction

How to Reconstitute

1

Wipe stopper.

2

2 mL BAC water per 2 mg vial.

3

Inject down inner wall. Swirl gently.

4

Refrigerate.

Dosing math: 1000 mcg/mL with 2 mL BAC water. For 200 mcg: 0.2 mL.

Quality Indicators

Good — use as normal

  • Clear solution after reconstitution

Acceptable

  • Very faint cloudiness clearing within 60 seconds

Discard immediately

  • Persistent cloudiness
  • Particulate
  • Discoloration

What to Expect

Week 1–2

Satellite cells activating. Muscle soreness may be more pronounced due to repair activation.

Week 3–8

Myonuclei increasing. Muscle size & density improvements, particularly in trained groups.

Community Insights

Self-reported. Reflects user experience, not clinical outcomes.

Verify what you have

Information on this page applies to pharmaceutical-grade peptides. Purity & identity of research-grade products vary. Certipep provides independent ESI-TOF-MS & HPLC analysis with a signed analytical report.

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