MK-677 vs Macimorelin
Head-to-head comparison of MK-677 (Ibutamoren Mesylate (MK-677)) and Macimorelin (Macimorelin acetate (AEZS-130)) — benefits, dosing, side effects, research data, and where to buy.
Research Score
| Property | MK-677 | Macimorelin |
|---|---|---|
| Category | Growth Hormone | Growth Hormone |
| Full Name | Ibutamoren Mesylate (MK-677) | Macimorelin acetate (AEZS-130) |
| Molecular Weight | 528.662 g/mol | N/A |
| Half-Life | ~24 hours | about 4-6 hours |
| Amino Acids | Non-peptide compound | N/A |
| Typical Dose | — | 0.5 mg/kg single oral dose |
| Route | — | Oral |
| Purity | >99% | ≥98% |
| Studies Count | 120 | 120 |
| Research Status | Active Research | 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
Macimorelin Benefits
- ✓diagnostic GH stimulation
- ✓single oral dose
- ✓rapid measurable GH response
- ✓high clinical utility
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.
Macimorelin Dosing
0.5 mg/kg orally as a single dose|fasted testing conditions|serial GH sampling after administration
MK-677 Side Effects
- ⚠Increased appetite, mild water retention, drowsiness, transient numbness, mild increase in fasting blood glucose with long-term use.
Macimorelin Side Effects
- ⚠dysgeusia or taste disturbance
- ⚠nausea
- ⚠headache
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.
Macimorelin
Macimorelin has been validated in clinical testing as an oral alternative to injectable GH stimulation tests. Its short-term use makes it a useful translational tool for evaluating pituitary GH reserve.
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