MK-677 vs HGH Fragment 176-191
Head-to-head comparison of MK-677 (Ibutamoren Mesylate (MK-677)) and HGH Fragment 176-191 (Human Growth Hormone Fragment 176-191) — benefits, dosing, side effects, research data, and where to buy.
Research Score
| Property | MK-677 | HGH Fragment 176-191 |
|---|---|---|
| Category | Growth Hormone | Weight Management |
| Full Name | Ibutamoren Mesylate (MK-677) | Human Growth Hormone Fragment 176-191 |
| Molecular Weight | 528.662 g/mol | 1817.12 g/mol |
| Half-Life | ~24 hours | ~30 minutes |
| Amino Acids | Non-peptide compound | 16 |
| Typical Dose | — | — |
| Route | — | — |
| Purity | >99% | >98% |
| Studies Count | 120 | 45 |
| Research Status | Active Research | Active Research |
MK-677 Benefits
- ✓Oral GH secretagogue, 24-hour GH elevation, increases IGF-1, improves sleep quality, increases lean mass, does not suppress natural GH
HGH Fragment 176-191 Benefits
- ✓Targeted fat loss, no blood sugar impact, no IGF-1 elevation, inhibits lipogenesis, stimulates lipolysis, improved body composition
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.
HGH Fragment 176-191 Dosing
250-500 mcg subcutaneously 1-2 times daily on empty stomach. 12-16 week cycles typical in research.
MK-677 Side Effects
- ⚠Increased appetite, mild water retention, drowsiness, transient numbness, mild increase in fasting blood glucose with long-term use.
HGH Fragment 176-191 Side Effects
- ⚠Injection site irritation, headache, drowsiness. Does not affect blood sugar, insulin sensitivity, or elevate IGF-1.
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.
HGH Fragment 176-191
This 16-amino-acid fragment specifically targets adipose tissue via beta-3 adrenergic receptors. Works through a GH-receptor-independent pathway, explaining selective fat-loss properties without growth-promoting effects.
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