MK-677
Ibutamoren
Oral non-peptide GHS-R1a agonist (ibutamoren). Svensson 1998 is real human pharmacology. Appetite and fasting-glucose creep are the usual costs. Not HGH, not a reconstitution peptide, WADA S2.
Use-case scores
0–10 against the evidence we have, not a gym ranking. Hidden domains do not apply here.
- Muscle / recomp5/10
Multiple small-to-moderate human GH/IGF-1 and body-comp studies (e.g. Svensson 1998, PMID 9626107). Ceiling 6.5; haircut for glucose, appetite, no obesity/GHD label.
- Recovery & sleep5/10
Sleep architecture changes show up in the human secretagogue literature. Not a licensed insomnia drug.
- Metabolic / weight3.5/10
Appetite and insulin resistance cut the other way from a fat-loss peptide. Do not score it like a GLP-1.
Compound card
- Sequence
- Non-peptide (ibutamoren mesylate)
- Class
- Oral GHS-R1a agonist (not a peptide; no reconstitution)
- Formula
- C27H36N4O5S
- Status
- Not FDA-approved · research use
How it works
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 oral non-peptide GHS-R1a agonist. Human GH/IGF-1 pharmacology is real. It was never approved as a drug. Appetite and fasting-glucose creep are the usual costs. WADA S2. Not a reconstitution peptide.
Research Use Cases
- ✓Oral GHS-R1a identity vs injectable GHRPs vs macimorelin
- ✓Why glucose watching belongs next to the hunger story
- ✓Not HGH and not a cutting GLP-1
Dosing
| Phase | Dose | Frequency | Notes |
|---|---|---|---|
| Starting Dose | 10 mg | Once daily (oral) | Start here to assess appetite and water retention tolerance. Take before bed. |
| Standard Protocol | 25 mg | Once daily (oral) | Most studied dose. Bedtime dosing leverages the natural nocturnal GH surge. |
Administration
Timeline
Who it is 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.
Limits of current evidence
- Oral. No BAC water. Capsules and liquids are not 5 mg cakes.
- Appetite and fasting-glucose creep are the usual costs. This is not a cutting GLP-1.
- WADA S2 (GH secretagogues). Not a loophole around somatropin.
Verdict
MK-677 is Merck’s oral ghrelin-mimetic small molecule, not a peptide vial. Svensson 1998 is real human pharmacology. It is not HGH, not FDA-approved for physique, and it can raise glucose. Do not put it in the reconstitution calculator.
Interactions & Contraindications
Fasting glucose and insulin. Water retention. Sleep apnea can worsen. Do not treat it as a GLP-1 partner for fat loss.
Synergies & Common Stacks
Two GH-axis tools. Additive IGF-1 is a monitoring problem, not a convenience stack to print as safe.
MK-677 vs. Ipamorelin
Canonical comparison: 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.
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
- Murphy MG, et al. “MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism.” J Clin Endocrinol Metab (1998). PMID: 9506738
- Nass R, et al. “Two-year effects of MK-677 on body composition in elderly adults.” J Clin Endocrinol Metab (2008). PMID: 18544658
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