MK-677
Orally active non-peptide GH secretagogue — once-daily pill elevates GH and IGF-1 with Phase II human RCT data.
Research facts
| Half-life | ~24 hours |
|---|---|
| Route | Oral |
| Typical dose | 10–25 mg/day |
| Frequency | Once daily (evening) |
| Solvent | N/A — oral tablet/capsule |
| pH | N/A |
| Stability | Room temperature |
Mechanism of action
MK-677 (ibutamoren) is an orally bioavailable, non-peptide GHS-R1a agonist (ghrelin mimetic). Unlike injectable GHRPs, it has excellent oral bioavailability and a 24-hour half-life, enabling once-daily dosing. It stimulates pulsatile GH release and sustained IGF-1 elevation. Phase II trials in elderly subjects demonstrated increases in muscle mass, bone density, and functional performance. A Phase III trial in hip fracture recovery showed improved gait speed and reduced falls. It significantly increases appetite (ghrelin pathway) and causes water retention and fasting glucose elevation, which limits its use in metabolic syndrome patients.
Documented effects (research-model)
- Oral bioavailability — no injections required
- Sustained GH and IGF-1 elevation (24h half-life)
- Phase II RCT data in elderly for muscle mass and bone density
- Phase III data in hip fracture recovery
- Sleep quality improvement (GH pulse during slow-wave sleep)
- Convenient once-daily evening dosing
Research protocols
| Protocol | Dose | Frequency | Cycle | Vial |
|---|---|---|---|---|
| Standard | 12.5–25 mg/day orally | Once daily (evening with or without food) | 12–24 weeks | Capsule/tablet formulation |
Research context only. Not medical advice. Consult a qualified healthcare professional before any protocol decision.
Synergies
- CJC-1295 MODERATE
CJC-1295 provides GHRH-mediated pulse amplification; MK-677 provides sustained GH elevation via oral route. Convenient when SubQ injections are not preferred.
Myths & misconceptions
Evidence gaps
- Fasting glucose elevation and insulin resistance with chronic use requires monitoring.
- Appetite stimulation and water retention are significant practical limitations.
- Long-term (>2 year) safety and IGF-1 levels not characterised in RCTs.
Safety notes
Monitor fasting glucose and HbA1c — insulin resistance is a real concern. Significant appetite stimulation. Water retention common initially. IGF-1 monitoring essential — keep within age-appropriate range. Not for use in active cancer or personal history of cancer (IGF-1 is mitogenic).
Biomarkers to monitor
Primary-source citations
- PMID 9467547 — MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism (J Clin Endocrinol Metab. 1998)
Frequently asked
What is MK-677?
MK-677 (Ibutamoren — Oral GH Secretagogue) is a research compound classified in our library as Tier B — Some human data + strong preclinical evidence.. Orally active non-peptide GH secretagogue — once-daily pill elevates GH and IGF-1 with Phase II human RCT data.
What is the evidence tier for MK-677?
We classify MK-677 as Tier B: Some human data + strong preclinical evidence. See our full peptide evidence tiers explainer for how we assign S/A/B/C/D.
What is the research dose of MK-677?
For MK-677, typical research dose is 10–25 mg/day, route is Oral, half-life is ~24 hours. Protocols vary by research goal — see the protocols section on this page for standard and advanced dosing schedules. Research use only, not medical advice.
Is MK-677 safe?
Monitor fasting glucose and HbA1c — insulin resistance is a real concern. Significant appetite stimulation. Research context only — no compound on this site is approved for human therapeutic use unless explicitly noted.