PinnyPeptide

IGF-1 LR3 vs MGF (Mechano Growth Factor)

Side-by-side comparison: effects, dosing ranges, side effects, regulatory status, and reconstitution.

Peptide A

IGF-1 LR3

Muscle Growth

Long-acting IGF-1 analog with reduced binding-protein affinity for sustained signaling.

Peptide B

MGF (Mechano Growth Factor)

Growth Hormone

A locally-acting IGF-1 splice variant released by muscle in response to mechanical load.

Typical vial

1 mg

Typical dose

20-50 mcg

Half-life

~20-30 hours

FDA status

Not FDA approved. Native recombinant rhIGF-1 (mecasermin/Inc…

Typical vial

2 mg

Typical dose

200-400 mcg

Half-life

~5-7 minutes (MGF); ~2-3 days (PEG-MGF)

FDA status

Not FDA approved for any indication.

IGF-1 LR3 effects

  • Sustained IGF-1 receptor activation (20-30 hour half-life)
  • Muscle cell hyperplasia (increased cell number, not just size)
  • Anabolic signaling via PI3K-Akt-mTOR pathway
  • Improved nutrient partitioning toward muscle
  • Enhanced recovery from training-induced damage

MGF (Mechano Growth Factor) effects

  • Activates muscle satellite cells and promotes proliferation
  • Accelerates muscle repair after mechanical damage
  • May enhance hypertrophy in response to training
  • Local action at injection site (non-pegylated form)
  • Systemic muscle and recovery signaling (PEG-MGF)

IGF-1 LR3 side effects

  • Hypoglycemia (real risk — IGF-1 has insulin-like activity)
  • Joint pain and stiffness
  • Carpal tunnel-like symptoms
  • Lethargy / lightheadedness from glucose drops
  • Possible tumor-promoting effects (theoretical, dose-dependent)
  • Localized lipohypertrophy or muscle asymmetry with site injection

MGF (Mechano Growth Factor) side effects

  • Injection-site irritation or redness
  • Mild hypoglycemia at high doses (insulin-like effect)
  • Possible hypertrophy of non-target tissues (theoretical)
  • Limited long-term safety data in humans

IGF-1 LR3 dosing ranges

Research / muscle hypertrophy

20-50 mcg · Once daily (SubQ or IM), pre- or post-workout · 30-50 days per cycle

Site-specific injection (research)

20-40 mcg per site · Into trained muscle, post-workout · 30-50 days per cycle

MGF (Mechano Growth Factor) dosing ranges

Localized muscle repair (non-pegylated)

200-300 mcg per site · Post-workout, into the worked muscle (intramuscular) · 3-4 weeks per cycle

Systemic muscle recovery (PEG-MGF)

200-400 mcg · Twice weekly (SubQ) · 4-6 weeks per cycle

IGF-1 LR3 vs MGF (Mechano Growth Factor) — common questions

What is the difference between IGF-1 LR3 and MGF (Mechano Growth Factor)?

IGF-1 LR3: Long-acting IGF-1 analog with reduced binding-protein affinity for sustained signaling. Typical dose 20-50 mcg. MGF (Mechano Growth Factor): A locally-acting IGF-1 splice variant released by muscle in response to mechanical load. Typical dose 200-400 mcg. Both fall under the Muscle Growth and Growth Hormone categories.

Can you stack IGF-1 LR3 and MGF (Mechano Growth Factor)?

Stacking IGF-1 LR3 with MGF (Mechano Growth Factor) is a protocol-design question best raised with a clinician — it depends on your goal, current bloodwork, and whether both peptides target overlapping mechanisms. Both peptides should be tracked independently with separate injection sites and timing. PinnyPeptide supports multi-peptide stacks with automatic injection site rotation.

Which is dosed more frequently, IGF-1 LR3 or MGF (Mechano Growth Factor)?

IGF-1 LR3 is typically dosed: Once daily (SubQ or IM), pre- or post-workout for Research / muscle hypertrophy; Into trained muscle, post-workout for Site-specific injection (research). MGF (Mechano Growth Factor) is typically dosed: Post-workout, into the worked muscle (intramuscular) for Localized muscle repair (non-pegylated); Twice weekly (SubQ) for Systemic muscle recovery (PEG-MGF).

Are IGF-1 LR3 and MGF (Mechano Growth Factor) FDA approved?

IGF-1 LR3: Not FDA approved. Native recombinant rhIGF-1 (mecasermin/Increlex) is FDA approved for severe primary IGF-1 deficiency in children, but IGF-1 LR3 itself is not. MGF (Mechano Growth Factor): Not FDA approved for any indication.

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