Source comparison
Ipamorelin vs MK-677: Research Comparison
This table directly compares the key research characteristics of ipamorelin vs MK-677, highlighting the pharmacokinetic, mechanistic, and practical differences that determine which compound suits specific experimental protocols. Mechanism Selective GHS-R1a ago
This comparison does not assign a generated winner or score.
- This table directly compares the key research characteristics of ipamorelin vs MK-677, highlighting the pharmacokinetic, mechanistic, and practical differences that determine which compound suits specific experimental protocols.
- Mechanism
- Selective GHS-R1a agonist; stimulates pulsatile GH release without ghrelin pathway activation
- Ghrelin receptor agonist; mimics endogenous ghrelin with sustained GH and appetite stimulation
- Ipamorelin isolates GH effects; MK-677 engages broader ghrelin-mediated physiology
- Half-Life
- ~2 hours (pulsatile release, rapid clearance)
- 24–28 hours (sustained receptor activation)
- Ipamorelin for acute studies; MK-677 for chronic protocols
- Bioavailability
- Injectable only (subcutaneous or intramuscular); degraded orally
- Orally bioavailable (capsule or liquid); no injection required
- MK-677 reduces injection frequency in long-term studies
- Dosing Frequency
- Once or twice daily (rodent: 100–300 mcg/kg)
- Once daily (rodent: 2–10 mg/kg; human observational: 25 mg)
- Ipamorelin requires more frequent dosing but allows temporal control
- Off-Target Effects
- Minimal; no cortisol, prolactin, or ACTH elevation
- Appetite stimulation, potential insulin resistance with chronic use
- Ipamorelin cleaner for metabolic studies; MK-677 affects hunger and glucose handling
- Washout Period
- <12 hours (rapid clearance)
- 5–7 days (prolonged plasma presence)
- Ipamorelin better for crossover or multi-phase study designs
- Best Use Cases
- Acute GH response, muscle protein synthesis, circadian studies, stress-sensitive models
- Chronic administration, aging research, sarcopenia, bone density, cachexia models
- Match compound to protocol duration and receptor activation pattern