Follistatin vs PEG-MGF
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
Follistatin
Follistatin is a glycoprotein that inhibits myostatin, the protein responsible for limiting muscle growth. By blocking myostatin, follistatin can theoretically allow for increased muscle development beyond natural limits.
Full details →PEG-MGF
PEG-MGF (PEGylated Mechano Growth Factor) is a variant of IGF-1 that is produced in response to muscle damage. PEGylation extends its half-life from minutes to several hours, making it practical for use.
Full details →Side-by-Side Comparison
| Aspect | Follistatin | PEG-MGF |
|---|---|---|
| Dose Range | 50 mcg–100 mcg | 400 mcg–1.2 mg |
| Frequency | 1x daily | Less than daily |
| Cycle Length | 2–4 weeks | 4–6 weeks |
| Route | subcutaneous | subcutaneous |
| Mechanism | Binds to and neutralizes myostatin and activin, both of which are negative regulators of muscle mass. This removes the natural brake on muscle growth, allowing for enhanced hypertrophy. | Activates muscle satellite cells (stem cells) and promotes their fusion to existing muscle fibers for repair and growth. MGF is produced naturally in response to mechanical stress on muscles. |
| Typical Dosage | Research protocols typically use 100-300mcg daily, though optimal dosing is not well established. Gene therapy approaches have also been studied. | Research protocols typically use 200-400mcg injected into targeted muscle groups 2-3 times weekly, usually post-workout. |
| Administration | Subcutaneous injection. Different isoforms exist (FS344, FS315) with varying properties. Requires careful sourcing due to complexity. | Intramuscular injection, ideally into muscles trained that day. Best administered post-workout when satellite cell activation is relevant. |
| Side Effects | Limited human data. Theoretical concerns about effects on other organs where activin signaling is important. | Injection site soreness, potential hypoglycemia, and localized swelling. Generally well-tolerated. |
| Best For |
What They Have in Common
Follistatin, PEG-MGF are both commonly used for:
Key Differences
Unique to PEG-MGF:
Which Has Stronger Evidence?
| Goal | Follistatin | PEG-MGF |
|---|---|---|
| Muscle Growth | medium | medium |
Key Studies
Follistatin
- Heart to Heal: Unveiling Follistatin's Potential for Myocardial Regeneration.
Circulation research, 2025
- Fructose and follistatin potentiate acute MASLD during complete hepatic insulin resistance.
Nature communications, 2025
- Follistatin drives neuropathic pain in mice through IGF1R signaling in nociceptive neurons.
Science translational medicine, 2024
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