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H1: MK-677 — Growth Hormone Secretagogue for Research Use Only
MK-677, also known as Ibutamoren mesylate, is a research-grade growth hormone secretagogue (GHS) that acts as a ghrelin receptor (GHS-R1a) agonist, stimulating the secretion of growth hormone (GH) and insulin-like growth factor-1 (IGF-1).
It is not approved for human or veterinary administration and is supplied exclusively for research use.
Researchers study MK-677 to explore endocrine, metabolic, and sleep physiology, as well as muscle and bone regeneration models.
Documentation: COA Hub
Safety reference: Peptide Safety
H2: Overview — What Is MK-677 (Ibutamoren)?
MK-677 (Ibutamoren) is a non-peptide GH secretagogue that mimics the action of endogenous ghrelin by binding to the growth hormone secretagogue receptor in the hypothalamus and pituitary gland.
Unlike traditional GH-releasing peptides, MK-677 is orally active and increases GH and IGF-1 levels without affecting cortisol.
In clinical and preclinical research, it has shown effects on lean mass preservation, improved sleep architecture, and enhanced bone metabolism.
Reference: Wikipedia
Key trial: PubMed
H2: Key Attributes of MK-677
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Compound type: Non-peptide GH secretagogue (ghrelin receptor agonist)
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Aliases: Ibutamoren, L-163,191, MK-677
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Mechanism: Stimulates GH and IGF-1 release via ghrelin receptor (PubMed)
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Research focus: Endocrine function, metabolic modeling, anabolic regeneration
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Molecular formula: C₂₇H₃₆N₄O₅S · CH₄O₃S
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Purity: ≥ 98% verified via COA Hub
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Storage: Store cool, dark, and dry per Peptide Safety
H2: Research Applications
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Growth hormone axis research: MK-677 elevates GH and IGF-1 for up to 24 hours post-dose (PubMed)
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Muscle and strength studies: Demonstrated anabolic activity through endocrine stimulation (PMC)
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Bone metabolism: Shown to improve bone turnover and density in aged animal models (PubMed)
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Sleep and recovery models: Increased REM and deep sleep duration (PubMed)
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Metabolic and anti-frailty research: Evaluated for appetite regulation, GH deficiency, and body composition in aging (PubMed)
See COA Guide for interpreting analytical data.
H2: Technical Specifications
| Attribute | Detail |
|---|---|
| Chemical Class | Non-peptide GH secretagogue |
| Form | Research-grade powder |
| Purity | ≥ 98% (COA Hub) |
| Solubility | Water / DMSO |
| Half-life | ~24 hours |
| Storage | 2–8 °C, protected from light |
| Regulatory Status | Research use only; not approved for therapeutic administration |
H2: Comparison Table — MK-677 vs LGD-4033 vs S4
| Property | MK-677 (Ibutamoren) | LGD-4033 (Ligandrol) | S4 (Andarine) |
|---|---|---|---|
| Compound Type | GH secretagogue | SARM | SARM |
| Mechanism | Ghrelin receptor agonist → GH/IGF-1 release | Full AR agonist | Partial AR agonist |
| Primary Focus | GH/IGF-1 axis activation | Lean mass & bone density | Muscle & bone selectivity |
| Anabolic Pathway | Endocrine-driven | Androgen receptor | Androgen receptor |
| Oral Bioavailability | ~60% | ~90% | ~50% |
| Half-life | ~24 h | ~24 h | ~6 h |
| Hormonal Effect | Increases GH/IGF-1 | Minimal GH change | None |
| Human Approval | Investigational | None | None |
Graphical overview:
GH/IGF-1 Activation: MK-677 ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
Muscle Growth: LGD-4033 ▓▓▓▓▓▓▓▓▓▓▓▓ S4 ▓▓▓▓▓▓▓▓
Bone Metabolism: MK-677 ▓▓▓▓▓▓▓▓▓▓▓ S4 ▓▓▓▓▓▓▓▓
Tissue Selectivity: S4 ▓▓▓▓▓▓▓▓▓ LGD-4033 ▓▓▓▓▓▓▓▓▓▓
H2: FAQ — MK-677 (Ibutamoren)
Q1. What is MK-677 used for in research?
It is used to model GH/IGF-1 axis stimulation, sleep physiology, and endocrine-metabolic interaction (PubMed).
Q2. Is MK-677 a SARM?
No — it is a growth hormone secretagogue, not an androgen receptor modulator (Wikipedia).
Q3. How does MK-677 compare to LGD-4033 or S4?
MK-677 stimulates GH and IGF-1 indirectly, while LGD-4033 and S4 act directly on the androgen receptor. See comparison table above.
Q4. How should MK-677 be stored?
Keep sealed, cool, dry, and away from light (Peptide Safety).
Q5. Is MK-677 approved for clinical use?
No — it is not approved for clinical or human use (DrugBank).
H2: Research Evidence — Key Studies
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GH & IGF-1 elevation study (PubMed)
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Bone density & turnover research (PubMed)
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Sleep quality and REM study (PubMed)
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Aging metabolism & frailty outcomes (PubMed)
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SARM vs GHS mechanistic contrasts (PMC)
Internal references:
COA Hub and COA Guide
| Weight | .06875 lbs |
|---|---|
| Dimensions | 2 × 2 × 4.25 in |
| Quantity |
60 capsules |
All products on this site are for research and development use only. Products are not for human consumption of any kind. The statements made on this website have not been evaluated by the US Food and Drug Administration. The statements and the products of this company are not intended to diagnose, treat, cure, or prevent any disease. Gentleman Peptide is a chemical supplier. Gentleman Peptide is not a compounding pharmacy or chemical compounding facility as defined under 503A of the Federal Food, Drug, and Cosmetic Act. Gentleman Peptide is not an outsourcing facility as defined under 503B of the Federal Food, Drug, and Cosmetic Act. All products are sold for research, laboratory, or analytical purposes only, and are not for human consumption. Gentleman Peptide’s Products are intended strictly for research purposes only. These products are not approved by the U.S. Food and Drug Administration (FDA) for human consumption or medical use. Under no circumstances should these peptides be used for any purpose other than research. By purchasing or using our peptides, you acknowledge and agree that you will use them solely in accordance with applicable laws and regulations and that you accept full responsibility for their use. Statements made on this website have not been evaluated by the USA Food and Drug Administration.
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