MK-677 // Oral GH Secretagogue
The only orally available growth hormone secretagogue. MK-677 is a non-peptide ghrelin mimetic with a 24-hour half-life — one daily oral dose sustains elevated GH and IGF-1 around the clock. No injections, no reconstitution, no cold storage. The convenience king of GH optimization, with the longest-running human study of any GH secretagogue (2 years).
One pill. 24 hours of elevated GH.
MK-677 is a small-molecule, non-peptide ghrelin mimetic developed by Merck. Unlike injectable GHRP peptides, it survives first-pass metabolism and reaches the ghrelin receptor (GHS-R1a) orally with excellent bioavailability. Its 24-hour half-life means a single daily dose maintains continuous GH and IGF-1 elevation — similar to CJC-1295 DAC but without injections. The trade-off: continuous rather than pulsatile GH release, and significant appetite stimulation.
One dose, morning or night. That's the whole protocol.
MK-677 is dosed orally at 10–25mg once daily. Some users take it at night to minimize daytime appetite and leverage the nocturnal GH pulse; others take it in the morning. The compound's 24-hour half-life means timing is less critical than consistency. Start at 10–12.5mg to assess appetite and glucose response before escalating.
The longest-studied GH secretagogue in humans.
MK-677 was developed by Merck and studied extensively through Phase 2 clinical trials for GH deficiency, sarcopenia, and frailty. The longest published study ran for 2 years in elderly subjects, demonstrating sustained IGF-1 elevation, improved body composition (increased lean mass, reduced fat mass), and no significant desensitization of the GH response.
The 2-year study showed IGF-1 levels increased to the youthful reference range and maintained that elevation throughout. Lean mass increased and fat mass decreased modestly. Sleep quality improved. The primary adverse effects were transient glucose elevation and appetite stimulation — both manageable.
Merck ultimately did not pursue FDA approval, likely due to the glucose concerns and the complex regulatory landscape for GH-related compounds. This left MK-677 in a research-compound limbo — well-studied with excellent data, but not commercially developed. It remains the most convenient GH secretagogue available and the only one that doesn't require injection.
MK-677 vs. the injectable GH field.
| Compound | Route | Duration | Convenience | Desensitization |
|---|---|---|---|---|
| MK-677 | Oral | 24 hours | Highest | None |
| CJC-1295 (DAC) | Injectable | 6–8 days | High | Unlikely |
| CJC-1295 + Ipa | Injectable | ~2–4 hours | Low | None |
| Sermorelin | Injectable | ~10–20 min | Moderate | None |
| Hexarelin | Injectable | ~70 min | Low | 4–8 weeks |
What to watch for.
MK-677's side effect profile is manageable with proper protocol adherence. Baseline blood work before starting and periodic monitoring during use is essential.
- Appetite stimulation (significant — plan accordingly)
- Water retention and bloating (especially first 2–4 weeks)
- Fasting glucose elevation (5–10 mg/dL, transient)
- Insulin resistance concerns with long-term use (monitor HbA1c)
- Lethargy and drowsiness (common, may benefit sleep if dosed at night)
- Vivid dreams (improved sleep architecture)
- Numbness/tingling in extremities (GH-mediated)
- Joint stiffness (dose-dependent)
- IGF-1 (primary efficacy marker — check at 4, 8, and 12 weeks)
- Fasting glucose (critical — check monthly for first 3 months)
- Fasting insulin (track insulin sensitivity)
- HbA1c (every 3 months — long-term glucose monitoring)
- Thyroid panel (GH affects T4→T3 conversion)
- Cortisol (morning draw)
- CBC and CMP
- DEXA for body composition at baseline and 12 weeks
- Can combine with CJC-1295 DAC for layered GH approach
- Can add Ipamorelin at bedtime for pulsatile boost on top of baseline
- BPC-157 / TB-500 for recovery support
- Berberine or Metformin may help manage glucose effects
- Do NOT combine with exogenous HGH
- Monitor glucose more closely than with injectable GH peptides
- Room temperature storage (capsules/liquid)
- No refrigeration required (major advantage)
- Protect from light and moisture
- Capsules: store in original container
- Liquid: keep tightly sealed
- Stable small molecule — much easier storage than peptides
Compounds that complement MK-677.
The convenience king — maximum simplicity, minimum hassle.
MK-677 is the easiest way to elevate GH and IGF-1 — period. One pill per day, room temperature storage, no injections, no reconstitution. The 2-year human study confirms sustained efficacy without desensitization. The trade-offs are real: appetite stimulation, water retention in the first month, and glucose effects that require monitoring. If you're insulin-resistant or pre-diabetic, proceed with caution. If you're metabolically healthy and want the lowest-barrier entry to GH optimization — or you simply refuse to inject — MK-677 is the answer. Monitor your fasting glucose religiously and consider nighttime dosing to minimize daytime appetite impact.
Our free Protocol Guide includes the complete MK-677 oral protocol — dosing, glucose management, IGF-1 optimization, and blood work panels.