MK-677
MK-677 (Ibutamoren) is a highly bioavailable, non-peptide oral spiropiperidine that revolutionized systemic secretagogue delivery. Instead of inducing a brief, acute pulse of Growth Hormone like injectable peptides, MK-677 generates a continuous, 24-hour "GH bleed" that drastically elevates baseline Insulin-Like Growth Factor 1 (IGF-1) for extended periods. Favored for its extreme convenience and profound impact on bone density, deep sleep architecture, and muscle retention, its continuous mechanism demands strict monitoring of fasting blood glucose due to its tendency to induce transient insulin resistance.
Quick Stats
Scientific Data
Mechanism of Action
MK-677 (Ibutamoren) is a non-peptide, orally-active growth hormone secretagogue that mimics ghrelin at the GHS-R1a receptor. Unlike injectable GH secretagogues, MK-677 is taken orally and has a long duration of action — a single daily dose elevates GH and IGF-1 levels for up to 24 hours. It does not suppress natural GH secretion, and studies show sustained efficacy over 12+ months without desensitization.
MK-677 increases lean body mass, improves sleep quality (particularly REM sleep depth), and enhances bone mineral density. It is commonly included in peptide discussions despite being a non-peptide small molecule because it targets the same receptor as peptide GHRPs.
Source: PMID: 9467534
Background & History
MK-677 (Ibutamoren) is an orally active non-peptide ghrelin mimetic developed by Merck in the 1990s. Unlike injectable GHRPs, its oral bioavailability (~60%) and 24-hour half-life enable once-daily dosing. Phase I/II trials (Murphy et al., NEJM 1998) demonstrated sustained GH and IGF-1 elevation over 12 months with improvement in lean body mass in elderly subjects. Despite multiple clinical trials, it has never been approved as a pharmaceutical. It remains the most widely used oral GH secretagogue in research and wellness contexts.
Research Use Cases
- ✓Oral GH elevation without injections — ideal for injection-averse users
- ✓Age-related GH deficiency (somatopause) management
- ✓Muscle mass preservation in caloric restriction or aging
- ✓Improved deep sleep quality via GH-mediated slow-wave sleep enhancement
- ✓IGF-1 elevation for recovery and cellular repair
Dosing Protocol
| Typical Dose | 10-25 mg/day (oral) |
| Frequency | 1× daily (oral) |
| Half-Life | ~5 hours (IGF-1 elevation 24h) |
Dosing Protocols
Starting Dose
Standard Protocol
Administration
Expected Timeline
Who Is It For?
GH / IGF-1 Optimization
HighOral convenience with 24-hour GH/IGF-1 elevation. No injections required.
Sleep Enhancement
HighDramatically increases REM sleep depth — one of the most reliable sleep interventions available.
Anti-Aging / Longevity
ModerateLong-term IGF-1 support and bone density benefits with manageable side effects.
Safety & Considerations
Not FDA-approved. Increases appetite and may elevate blood glucose and water retention. Monitor fasting glucose. Not suitable for diabetics without medical supervision. No reconstitution needed.
Regulatory & Legal Status
Competitive athletes subject to anti-doping controls should not use MK-677.
Research Chemical
US Compounding: Not eligible / not available
⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.
Interactions & Contraindications
Elevates fasting glucose and insulin — do not use with insulin resistance, pre-diabetes, or T2D without medical supervision. Water retention common at higher doses. Hunger stimulation (ghrelin effect) makes caloric restriction difficult. May exacerbate sleep apnea. Avoid combining with GLP-1 agonists (opposing metabolic effects).
Synergies & Common Stacks
Dual-pathway GH elevation: CJC-1295 via GHRH receptor and MK-677 via ghrelin receptor. Additive effect on GH/IGF-1 with convenient weekly + daily dosing.
MK-677 elevates GH/IGF-1 for systemic anabolic effects; BPC-157 handles tissue-specific repair — useful combined recovery protocol.
MK-677 vs. Ipamorelin
| Attribute | MK-677 | Ipamorelin |
|---|---|---|
| Administration | Oral (daily capsule/liquid) | Subcutaneous injection (daily) |
| Mechanism | Ghrelin receptor agonist (oral GHRP) | Ghrelin receptor agonist (injectable GHRP) |
| GH/IGF-1 Elevation | Sustained 24-hr elevation | Pulsatile — lasts ~2 hrs post-injection |
| Appetite | Strong hunger stimulation | Minimal appetite stimulation |
| Water Retention | Notable — common early | Minimal |
| Sleep Quality | Strong improvement reported | Mild improvement |
Verdict: MK-677 offers the convenience of oral dosing with sustained 24-hour IGF-1 elevation but causes more hunger and water retention than Ipamorelin. Many users combine both for pulsatile + basal GH coverage.
Dosing Quick Reference
Frequently Asked Questions
Is MK-677 a peptide?▼
What is the standard MK-677 dose?▼
Does MK-677 cause desensitization?▼
References
- Svensson J et al. “"Two-month treatment of obese subjects with the oral GH secretagogue MK-677".” Journal of Clinical Endocrinology & Metabolism (1998). PMID: 9626107
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