Human Growth Hormone (HGH) vs IGF-1 LR3 vs MK-677 (Ibutamoren)
A three-way comparison to help you find the right peptide for your research goals.
Human Growth Hormone (HGH)
Human Growth Hormone (somatropin) is a 191-amino acid protein identical to naturally produced GH. FDA-approved for growth hormone deficiency, Turner syndrome, and other conditions. Widely used off-label for anti-aging and performance.
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 | Human Growth Hormone (HGH) | IGF-1 LR3 | MK-677 (Ibutamoren) |
|---|---|---|---|
| Mechanism | Binds to GH receptors throughout the body, stimulating IGF-1 production in the liver. Promotes protein synthesis, fat metabolism, and cellular regeneration across multiple tissues. | 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 | Medical: 0.1-0.3mg/kg/week divided into daily doses. Anti-aging: 1-2 IU daily. Performance: 2-6 IU daily, sometimes higher. | 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, preferably at night to mimic natural pulsatile release. Rotate injection sites. Store refrigerated. | 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 | Joint pain, water retention, carpal tunnel syndrome, potential insulin resistance, and acromegaly features with long-term high doses. | 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
Human Growth Hormone (HGH), IGF-1 LR3, MK-677 (Ibutamoren) are all commonly used for:
Key Differences
Unique to Human Growth Hormone (HGH):
Unique to MK-677 (Ibutamoren):
Detailed Analysis
Commonalities
Both Human Growth Hormone (HGH) and IGF-1 LR3 are commonly used for Muscle Growth, Fat Loss, Recovery & Healing.
Which Should You Choose?
Human Growth Hormone (HGH) has stronger evidence for Fat Loss, Recovery & Healing.
Commonalities
Both Human Growth Hormone (HGH) and MK-677 (Ibutamoren) are commonly used for Muscle Growth, Fat Loss, Recovery & Healing, Sleep Quality.
Which Should You Choose?
Human Growth Hormone (HGH) has stronger evidence for Fat Loss, Recovery & Healing. 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.