PinnyPeptide

Follistatin vs IGF-1 LR3

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

IGF-1 LR3

Muscle Growth

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

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

1 mg

Typical dose

20-50 mcg

Half-life

~20-30 hours

FDA status

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

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

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

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

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

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)

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

Follistatin vs IGF-1 LR3 — common questions

What is the difference between Follistatin and IGF-1 LR3?

Follistatin: Endogenous activin/myostatin binding protein — the gene-therapy myostatin inhibitor. Typical dose 100-300 mcg. IGF-1 LR3: Long-acting IGF-1 analog with reduced binding-protein affinity for sustained signaling. Typical dose 20-50 mcg. Both fall under the Muscle Growth category.

Can you stack Follistatin and IGF-1 LR3?

Stacking Follistatin with IGF-1 LR3 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 IGF-1 LR3?

Follistatin is typically dosed: Daily (SubQ) for Research / muscle hypertrophy (recombinant); One-time for AAV gene therapy (clinical). 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).

Are Follistatin and IGF-1 LR3 FDA approved?

Follistatin: Not FDA approved as recombinant protein. AAV-Follistatin gene therapy in clinical trials. 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.

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