GHRP-2 vs IGF-1 LR3 vs MK-677 (Ibutamoren)
A three-way comparison to help you find the right peptide for your research goals.
GHRP-2
Growth Hormone Releasing Peptide 2 (GHRP-2) is considered one of the most potent GHRPs available. It provides strong GH release with moderate hunger increase compared to GHRP-6.
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 →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 →Side-by-Side Comparison
| Aspect | GHRP-2 | IGF-1 LR3 | MK-677 (Ibutamoren) |
|---|---|---|---|
| Mechanism | Binds to the ghrelin receptor (GHS-R) to stimulate GH release from the pituitary. Also has some direct effects on the hypothalamus. Causes less appetite increase than GHRP-6. | 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. |
| Typical Dosage | Typical dosing: 100-300mcg administered 2-3 times daily. Often stacked with GHRH peptides for enhanced GH release. | 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. |
| Administration | Subcutaneous injection on an empty stomach. Can be used at bedtime to enhance natural GH pulse during sleep. | 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. |
| Side Effects | Moderate hunger increase, water retention, potential prolactin and cortisol elevation (less than GHRP-6), tingling sensations. | 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. |
| Best For |
What They Have in Common
GHRP-2, IGF-1 LR3, MK-677 (Ibutamoren) are all commonly used for:
Key Differences
Unique to GHRP-2:
Unique to IGF-1 LR3:
Unique to MK-677 (Ibutamoren):
Detailed Analysis
Commonalities
Both GHRP-2 and IGF-1 LR3 are commonly used for Muscle Growth, Fat Loss.
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 GHRP-2 and MK-677 (Ibutamoren) are commonly used for Muscle Growth, Fat Loss, Sleep Quality.
Which Should You Choose?
MK-677 (Ibutamoren) has stronger evidence for Sleep Quality.
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.