HGH Fragment 176-191 vs IGF-1 LR3
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
HGH Fragment 176-191
HGH Fragment 176-191 is the fat-reducing portion of the growth hormone molecule. Unlike AOD-9604 (which has an additional tyrosine), this is the exact fragment of HGH responsible for lipolytic effects.
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 | HGH Fragment 176-191 | IGF-1 LR3 |
|---|---|---|
| Dose Range | 250 mcg–500 mcg | 20 mcg–100 mcg |
| Frequency | 2x daily | 1x daily |
| Cycle Length | 12–16 weeks | 4–6 weeks |
| Route | subcutaneous | subcutaneous |
| Mechanism | Mimics the lipolytic region of growth hormone, stimulating fat breakdown and inhibiting lipogenesis without affecting blood sugar or promoting growth. Works independently of GH receptors. | 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 | Typical dosing: 250-500mcg daily, often split into 2-3 doses. Usually administered on empty stomach, often with fasted cardio. | Research protocols typically use 20-100mcg daily, often divided into multiple injections or administered bilaterally to target muscles. |
| Administration | Subcutaneous injection. Best results when used fasted and combined with exercise. Avoid eating for 30 minutes post-injection. | Intramuscular injection (site-specific growth) or subcutaneous for systemic effects. Often cycled 4-6 weeks on, equal time off. |
| Side Effects | Generally well-tolerated. May cause injection site irritation, temporary lethargy, or headache. Does not affect blood glucose significantly. | Hypoglycemia, joint pain, water retention, potential jaw/hand growth with extended use, and injection site reactions. |
| Best For |
What They Have in Common
HGH Fragment 176-191, IGF-1 LR3 are both commonly used for:
Key Differences
Unique to IGF-1 LR3:
Which Has Stronger Evidence?
| Goal | HGH Fragment 176-191 | IGF-1 LR3 |
|---|---|---|
| Fat Loss | 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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