Follistatin vs IGF-1 LR3
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 →IGF-1 LR3
IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a modified version of IGF-1 with extended half-life and enhanced potency. The modifications prevent binding to IGF binding proteins, increasing bioavailability.
Full details →Side-by-Side Comparison
| Aspect | Follistatin | IGF-1 LR3 |
|---|---|---|
| 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. | Binds to IGF-1 receptors to promote protein synthesis, muscle growth, and fat metabolism. The LR3 modification (13 amino acid extension and arginine substitution) extends half-life from minutes to 20-30 hours. |
| 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 20-100mcg daily, often divided into multiple injections or administered bilaterally to target muscles. |
| Administration | Subcutaneous injection. Different isoforms exist (FS344, FS315) with varying properties. Requires careful sourcing due to complexity. | Intramuscular injection (site-specific growth) or subcutaneous for systemic effects. Often cycled 4-6 weeks on, equal time off. |
| Side Effects | Limited human data. Theoretical concerns about effects on other organs where activin signaling is important. | Hypoglycemia, joint pain, water retention, potential jaw/hand growth with extended use, and injection site reactions. |
| Best For |
What They Have in Common
Both Follistatin and IGF-1 LR3 are commonly used for: