IGF-1 LR3 vs MK-677 (Ibutamoren) vs TB-500
A three-way comparison to help you find 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 →MK-677 (Ibutamoren)
MK-677, also known as Ibutamoren, is an orally active growth hormone secretagogue. Unlike peptides, it can be taken orally and has a long half-life, providing 24-hour GH elevation.
Full details →TB-500
Thymosin Beta-4 (TB-500) is a naturally occurring peptide present in almost all human and animal cells. It plays a crucial role in tissue repair and regeneration.
Full details →Side-by-Side Comparison
| Aspect | IGF-1 LR3 | MK-677 (Ibutamoren) | TB-500 |
|---|---|---|---|
| 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. | Acts as a potent, selective agonist of the ghrelin receptor (GHS-R1a). Increases GH and IGF-1 levels without affecting cortisol. Mimics ghrelin's GH-releasing effects. | TB-500 promotes cell migration and differentiation, regulates actin (a cell-building protein), and reduces inflammation. It supports the formation of new blood vessels and wound healing. |
| Typical Dosage | Research protocols typically use 20-100mcg daily, often divided into multiple injections or administered bilaterally to target muscles. | Typical dosing: 10-25mg taken orally once daily. Often taken at night due to sleep benefits and appetite increase. | Research protocols typically use 2-2.5mg twice weekly during the loading phase, followed by maintenance dosing of 2mg every 2 weeks. |
| Administration | Intramuscular injection (site-specific growth) or subcutaneous for systemic effects. Often cycled 4-6 weeks on, equal time off. | Oral administration (capsule or liquid). Can be taken with or without food. Long half-life allows once-daily dosing. | Administered via subcutaneous or intramuscular injection. Some protocols suggest injection near injury sites. |
| Side Effects | Hypoglycemia, joint pain, water retention, potential jaw/hand growth with extended use, and injection site reactions. | Increased appetite and water retention are most common. May cause lethargy, vivid dreams, and mild numbness. Can affect blood glucose and insulin sensitivity. | May cause temporary fatigue, headache, or localized irritation at injection sites. |
| Best For |
What They Have in Common
IGF-1 LR3, MK-677 (Ibutamoren), TB-500 are all commonly used for:
Key Differences
Unique to IGF-1 LR3:
Unique to MK-677 (Ibutamoren):
Detailed Analysis
Commonalities
Both IGF-1 LR3 and MK-677 (Ibutamoren) are commonly used for Muscle Growth, Fat Loss, Recovery & Healing.
Which Should You Choose?
Both peptides have similar evidence levels for their shared goals. Your choice may depend on specific use case, availability, or personal response.
Commonalities
Both IGF-1 LR3 and TB-500 are commonly used for Muscle Growth, Recovery & Healing.
Which Should You Choose?
IGF-1 LR3 has stronger evidence for Muscle Growth. TB-500 has stronger evidence for Recovery & Healing.
Commonalities
Both MK-677 (Ibutamoren) and TB-500 are commonly used for Muscle Growth, Recovery & Healing.
Which Should You Choose?
MK-677 (Ibutamoren) has stronger evidence for Muscle Growth. TB-500 has stronger evidence for Recovery & Healing.