Source comparison
MK-677 Signaling Pathway: Peptide Comparison
MK-677 (Ibutamoren) GHSR1a agonist. Mimics ghrelin to trigger GHRH release and suppress somatostatin Amplifies natural pulsatile secretion without flattening rhythm 60–90% increase sustained over 24 hours Yes. Half-life 4–6 hours, once-daily dosing None. Does
This comparison does not assign a generated winner or score.
- MK-677 (Ibutamoren)
- GHSR1a agonist. Mimics ghrelin to trigger GHRH release and suppress somatostatin
- Amplifies natural pulsatile secretion without flattening rhythm
- 60–90% increase sustained over 24 hours
- Yes. Half-life 4–6 hours, once-daily dosing
- None. Does not suppress endogenous axis
- GHRP-2
- Synthetic GH secretagogue. GHSR1a agonist with similar mechanism to MK-677
- Increases pulse amplitude and frequency acutely
- Short-lived elevation (2–4 hours post-injection)
- No. Requires subcutaneous injection multiple times daily
- Minimal with proper cycling
- Exogenous GH (Somatropin)
- Direct GH replacement. Bypasses hypothalamic-pituitary signaling
- Eliminates natural pulsatility. Produces flat, sustained elevation
- Supraphysiological. IGF-1 exceeds normal range
- No. Injection only
- Yes. Suppresses endogenous GH secretion via negative feedback
- CJC-1295 (DAC)
- GHRH analog. Extends GHRH half-life to sustain GH release
- Blunted pulsatility. Sustained GH elevation over days
- Moderate sustained increase (40–60%)
- No. Injection required
- Moderate. Prolonged GHRH analog presence may reduce responsiveness
- Sermorelin
- GHRH analog. Stimulates pituitary GH release directly
- Preserves pulsatility with enhanced amplitude
- Modest increase (20–40%), limited by endogenous feedback
- No. Injection required, short half-life (~10 min)
- None. Works within natural feedback loop