MK-677 vs IGF-1 LR3
Head-to-head comparison of MK-677 (Ibutamoren Mesylate (MK-677)) and IGF-1 LR3 (Insulin-like Growth Factor-1 Long R3) — benefits, dosing, side effects, research data, and where to buy.
| Property | MK-677 | IGF-1 LR3 |
|---|---|---|
| Category | Growth Hormone | Performance |
| Full Name | Ibutamoren Mesylate (MK-677) | Insulin-like Growth Factor-1 Long R3 |
| Molecular Weight | 528.662 g/mol | 9,117 Da |
| Half-Life | ~24 hours | ~20-30 hours |
| Amino Acids | Non-peptide compound | 83 |
| Typical Dose | — | 20-100 mcg |
| Route | — | IM / SC |
| Purity | >99% | — |
| Studies Count | 120 | 298 |
| Research Status | Active Research | Pre-clinical |
MK-677 Benefits
- ✓Oral GH secretagogue, 24-hour GH elevation, increases IGF-1, improves sleep quality, increases lean mass, does not suppress natural GH
IGF-1 LR3 Benefits
- ✓Promotes muscle hyperplasia (new muscle cells)
- ✓Extended half-life vs native IGF-1
- ✓Enhanced protein synthesis
- ✓Improved nutrient partitioning
- ✓Anti-catabolic effects
MK-677 Dosing
10-25 mg orally once daily before bedtime. 25 mg is the most studied dose. Can be used long-term without cycling.
IGF-1 LR3 Dosing
Standard: 20-50 mcg IM post-workout|Advanced: 50-100 mcg IM or SC daily|Cycle: 4-6 weeks on, 4 weeks off
MK-677 Side Effects
- ⚠Increased appetite, mild water retention, drowsiness, transient numbness, mild increase in fasting blood glucose with long-term use.
IGF-1 LR3 Side Effects
- ⚠Common: Hypoglycemia (dose-dependent), joint pain, water retention
- ⚠Moderate: Gut growth concern (high doses), acromegaly-like symptoms
- ⚠Serious: Theoretical cancer risk (prolonged high-dose use)
Research Overview
MK-677
A landmark 2-year study in elderly adults demonstrated significant increases in lean mass, GH pulsatility, and IGF-1 to youthful ranges. Selectively agonizes GHS-R1a without increasing cortisol or prolactin.
IGF-1 LR3
IGF-1 LR3 has extensive in vitro and animal data. Its role in muscle hyperplasia is well-documented. The extended half-life modification provides practical advantages over native IGF-1.
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