Tirzepatide vs IGF-1 LR3
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
Tirzepatide
Tirzepatide is a first-in-class dual GIP/GLP-1 receptor agonist. FDA-approved as Mounjaro (diabetes) and Zepbound (weight loss), it has shown superior weight loss results compared to semaglutide in clinical trials.
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 | Tirzepatide | IGF-1 LR3 |
|---|---|---|
| Mechanism | Activates both GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 receptors, providing synergistic effects on insulin secretion, appetite suppression, and metabolic regulation. The dual mechanism may explain its enhanced efficacy. | 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 | Start at 2.5mg weekly, titrate every 4 weeks through 5mg, 7.5mg, 10mg, 12.5mg, to maximum 15mg weekly. Full titration takes approximately 20 weeks. | Research protocols typically use 20-100mcg daily, often divided into multiple injections or administered bilaterally to target muscles. |
| Administration | Subcutaneous injection once weekly. Rotate injection sites. Slower titration may help reduce GI side effects. | Intramuscular injection (site-specific growth) or subcutaneous for systemic effects. Often cycled 4-6 weeks on, equal time off. |
| Side Effects | Similar to semaglutide: nausea, diarrhea, vomiting, constipation, abdominal pain, decreased appetite. Generally improve with continued use. | Hypoglycemia, joint pain, water retention, potential jaw/hand growth with extended use, and injection site reactions. |
| Best For |
What They Have in Common
Both Tirzepatide and IGF-1 LR3 are commonly used for: