PinnyPeptide

Follistatin vs MGF (Mechano Growth Factor)

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

Peptide A

Follistatin

Muscle Growth

Endogenous activin/myostatin binding protein — the gene-therapy myostatin inhibitor.

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

100-300 mcg

Half-life

~30 minutes (recombinant); years (AAV expression)

FDA status

Not FDA approved as recombinant protein. AAV-Follistatin gen…

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.

Follistatin effects

  • Binds and neutralizes myostatin, activin A, and GDF-11
  • Promotes skeletal muscle hypertrophy
  • Increases muscle fiber size and strength
  • May enhance recovery from muscle injury
  • Sustained effect when delivered via AAV gene therapy

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)

Follistatin side effects

  • Limited human safety data for recombinant protein
  • Theoretical disruption of HPG axis (activin binding)
  • Injection-site reactions
  • Potential off-target effects on tissues using activin signaling

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

Follistatin dosing ranges

Research / muscle hypertrophy (recombinant)

100-300 mcg · Daily (SubQ) · 10-30 days per cycle

AAV gene therapy (clinical)

Single high-titer AAV infusion · One-time · Durable expression (years)

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

Follistatin vs MGF (Mechano Growth Factor) — common questions

What is the difference between Follistatin and MGF (Mechano Growth Factor)?

Follistatin: Endogenous activin/myostatin binding protein — the gene-therapy myostatin inhibitor. Typical dose 100-300 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 Follistatin and MGF (Mechano Growth Factor)?

Stacking Follistatin 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, Follistatin or MGF (Mechano Growth Factor)?

Follistatin is typically dosed: Daily (SubQ) for Research / muscle hypertrophy (recombinant); One-time for AAV gene therapy (clinical). 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 Follistatin and MGF (Mechano Growth Factor) FDA approved?

Follistatin: Not FDA approved as recombinant protein. AAV-Follistatin gene therapy in clinical trials. MGF (Mechano Growth Factor): Not FDA approved for any indication.

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