IGF-1 LR3 vs PEG-MGF
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
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 →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 | IGF-1 LR3 | PEG-MGF |
|---|---|---|
| Dose Range | 20 mcg–100 mcg | 400 mcg–1.2 mg |
| Frequency | 1x daily | Less than daily |
| Cycle Length | 4–6 weeks | 4–6 weeks |
| Route | subcutaneous | subcutaneous |
| Mechanism | 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. | 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 20-100mcg daily, often divided into multiple injections or administered bilaterally to target muscles. | Research protocols typically use 200-400mcg injected into targeted muscle groups 2-3 times weekly, usually post-workout. |
| Administration | Intramuscular injection (site-specific growth) or subcutaneous for systemic effects. Often cycled 4-6 weeks on, equal time off. | Intramuscular injection, ideally into muscles trained that day. Best administered post-workout when satellite cell activation is relevant. |
| Side Effects | Hypoglycemia, joint pain, water retention, potential jaw/hand growth with extended use, and injection site reactions. | Injection site soreness, potential hypoglycemia, and localized swelling. Generally well-tolerated. |
| Best For |
What They Have in Common
IGF-1 LR3, PEG-MGF are both commonly used for:
Key Differences
Unique to IGF-1 LR3:
Which Has Stronger Evidence?
- Muscle Growth: IGF-1 LR3 has stronger research support.
| Goal | IGF-1 LR3 | PEG-MGF |
|---|---|---|
| Muscle Growth | high | medium |
| Recovery & Healing | medium | medium |
Key Studies
IGF-1 LR3
- IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep.
American journal of physiology. Endocrinology and metabolism, 2025
- Revolutionary decellularized Alstroemeria stem-based nerve conduit integrated with GelMA and controlled IGF-1 LR3 release for enhanced rat sciatic nerve regeneration.
International journal of biological macromolecules, 2025
- Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets.
Journal of developmental origins of health and disease, 2023
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