MK-677
MK-677 (Ibutamoren) is a selective ghrelin receptor agonist that stimulates growth hormone release without suppressing natural production.
Also known as: Ghrelin Receptor Agonist, Growth Hormone Secretagogue
Overview
MK-677 (Ibutamoren) is a selective ghrelin receptor agonist that stimulates growth hormone release without suppressing natural production. This orally active compound increases IGF-1 levels, improves sleep quality, and supports body composition changes through sustained growth hormone elevation.
Key Benefits
- Muscle Preservation
- Body Composition
- Bone Health
97% increase in 24-hour growth hormone secretion, 40-72% IGF-1 elevation, improved sleep quality, enhanced body composition, and sustained effects without suppressing natural GH production.
Mechanism of Action
MK-677 mimics endogenous ghrelin by binding to GHS-R1a receptors in the hypothalamus and pituitary, triggering pulsatile growth hormone release while maintaining natural circadian patterns. Superior >60% oral bioavailability eliminates injection requirements with 24-hour half-life enabling once-daily dosing.
Research Protocols Oral
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Body composition/Anti-aging | 25mg | 1x daily | Oral |
| Sleep quality improvement | 25mg | 1x nightly | Oral |
| Conservative start | 12.5mg | 1x daily | Oral |
| Research protocol | 25mg | 1x daily | Oral |
Research protocols from published literature — not dosing recommendations.
Peptide Interactions
- CJC-1295 — Synergistic: Complementary GH pathways - CJC-1295 provides pulsatile release while MK-677 maintains baseline elevation
- Ipamorelin — Synergistic: Both stimulate GH release through different mechanisms, creating pharmaceutical-grade hormone levels
- GHRP-2 — Synergistic: MK-677's sustained baseline elevation combines with GHRP-2's strategic pulsatile spikes
- TB-500 — Compatible: MK-677 enhances recovery and tissue repair effects through systemic growth factor elevation
- BPC-157 — Compatible: Non-competing mechanisms - MK-677 provides systemic growth factors while BPC-157 offers localized healing
- HGH — Avoid Combination: Redundant effects without proportional benefits - may increase side effect risk
- Insulin — Use Caution: MK-677 decreases insulin sensitivity - requires careful blood glucose monitoring with diabetes medications
- LGD-4033 — Use Caution: Case report shows 85.7% testosterone suppression and 95.8% liver enzyme elevation when combined
What to Expect Oral
Week 1-2: Improved sleep quality, vivid dreams, possible appetite increase. Week 2-4: Enhanced recovery, better sleep architecture, initial body composition changes. Week 4-8: Noticeable lean mass gains, continued sleep benefits. Week 8-12: Maximum body composition improvements, sustained GH elevation. Side effects: Appetite stimulation (>50%), water retention (30-40%), possible lethargy (20-30%).
Side Effects & Safety
FDA warns of 'significant safety risks due to potential for congestive heart failure'. Contraindicated in heart disease, diabetes, active cancer, severe cardiovascular disease. Decreases insulin sensitivity - monitor blood glucose closely. May cause 5-15mg/dL fasting glucose elevation. Requires baseline and ongoing monitoring: glucose, HbA1c, liver function, IGF-1. Not approved by FDA - investigational drug status only.
FDA warns of 'significant safety risks due to potential for congestive heart failure'. Contraindicated in heart disease, diabetes, active cancer, severe cardiovascular disease. Decreases insulin sensitivity - monitor blood glucose closely. May cause 5-15mg/dL fasting glucose elevation. Requires baseline and ongoing monitoring: glucose, HbA1c, liver function, IGF-1. Not approved by FDA - investigational drug status only.
Community Insights
MK-677 should be stored at Room temperature, cool dry place.
References
- A Study of the Metabolism of Ibutamoren (MK-677), a Growth Hormone Secretagogue, in Human Urine by Ultra-High-Performance Liquid Chromatography–High-Resolution Mass Spectrometry
- LGD-4033 and MK-677 use impacts body composition, circulating biomarkers, and skeletal muscle androgenic hormone and receptor content: A case report
- Structural basis of human ghrelin receptor signaling by ghrelin and the synthetic agonist ibutamoren
- Effect of the Orally Active Growth Hormone Secretagogue MK-677 on Somatic Growth in Rats
- MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study
- Hip Fracture Recovery Trial - Terminated
- Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial
- Bone Turnover Markers Study
- MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism
- Two-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure
- Reversal of Diet-Induced Catabolism
- Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man
- Sleep Quality Improvement Study
- Stimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretogogue (MK-677) in healthy elderly subjects
Research reference only. Not medical advice.