Source comparison
Comparison Table: Ipamorelin vs MK-677 Across Research Parameters
Mechanism Selective GHS-R1a agonist; pulsatile GH release mimicking natural secretion Ghrelin receptor agonist; sustained 24-hour GH elevation Ipamorelin preserves physiological pulse architecture; MK-677 creates pharmacological override Administration Subcuta
This comparison does not assign a generated winner or score.
- Mechanism
- Selective GHS-R1a agonist; pulsatile GH release mimicking natural secretion
- Ghrelin receptor agonist; sustained 24-hour GH elevation
- Ipamorelin preserves physiological pulse architecture; MK-677 creates pharmacological override
- Administration
- Subcutaneous injection, 1–3x daily, requires reconstitution
- Oral capsule/liquid, once daily, no preparation
- MK-677 wins on convenience; ipamorelin wins on dosing precision
- GH Release Pattern
- Discrete 90–120 minute pulses, 2–3 hours return to baseline
- Sustained elevation for 24 hours post-dose
- Pulsatile (ipamorelin) suits circadian research; sustained (MK-677) suits continuous anabolism models
- IGF-1 Elevation
- 40–60% above baseline at 300 mcg 2x daily
- 60–80% above baseline at 25 mg daily
- Comparable IGF-1 outcomes; mechanism and secondary effects differentiate them
- Cortisol Impact
- Zero measurable elevation across all doses tested
- 20–35% elevation from baseline in extended trials
- Ipamorelin is cortisol-neutral; MK-677 activates HPA axis unavoidably
- Prolactin Impact
- No effect on prolactin secretion
- Minimal to no effect (ghrelin pathways don't cross-activate prolactin)
- Both are prolactin-neutral
- Glucose Regulation
- No effect on fasting glucose or insulin sensitivity
- 8–15 mg/dL fasting glucose increase; mild insulin antagonism
- Ipamorelin is metabolically neutral; MK-677 requires glucose monitoring
- Appetite Effect
- No appetite stimulation
- Significant increase in hunger signaling (70–85% of subjects)
- MK-677's ghrelin mimicry confounds body composition research unless controlled
- Receptor Desensitisation Risk
- Low (pulsatile signaling prevents downregulation)
- Moderate (sustained activation may reduce sensitivity over 12+ weeks)
- Ipamorelin supports longer protocols without tolerance; MK-677 may require cycling
- Storage Requirements
- Refrigeration at 2–8°C post-reconstitution; 28-day stability
- Room temperature stable; no cold chain required
- MK-677 eliminates cold-chain logistics; ipamorelin requires temperature discipline
- Cost Per Month (Research Grade)
- $180–$240 for 10 mg supply (200 mcg 2x daily dosing)
- $120–$180 for 750 mg supply (25 mg daily dosing)
- MK-677 is 25–35% less expensive at equivalent IGF-1 elevation
- Ideal Research Application
- Protocols requiring cortisol-neutral GH elevation, precise dose timing, or circadian rhythm alignment
- Continuous anabolic signaling models, convenience-prioritised protocols, appetite research
- Choose based on whether secondary endocrine neutrality or administration simplicity drives protocol success