MK‑677 (Ibutamoren Mesylate) – Injectable Solution (Research Use Only)

CAS Number: 159634‑47‑6
Molecular Formula (Mesylate Salt): C₂₈H₄₀N₄O₈S · CH₄O₃S
Molecular Weight: 624.77 g/mol

For Preclinical Research Use Only

This product is not approved for human use. It is intended exclusively for laboratory research in vitro or in approved animal studies conducted by licensed researchers and institutions. Not for diagnostic or therapeutic use.

Pharmacological Profile

Ibutamoren (MK-677) is a potent, long-acting non-peptide ghrelin receptor (GHS-R1a) agonist that promotes endogenous secretion of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). Its mechanism of action mimics ghrelin, stimulating the hypothalamic-pituitary axis without affecting cortisol levels.

• Primary Action: GH secretagogue

• Receptor Target: GHS-R1a (Growth Hormone Secretagogue Receptor)

• Reported Effects in Animal & Clinical Models:

  • Sustained increases in GH and IGF‑1

  • Improved lean body mass and bone density

  • Enhanced tissue repair and metabolic regulation

  • Potential improvements in sleep architecture

Formulation Details

• Concentration: 25–50 mg/mL

• Solvent: Bacteriostatic water (0.9% benzyl alcohol)

• Purity: ≥98% (by HPLC)

• Appearance: Clear, sterile injectable solution

• Packaging: Amber glass vial, sealed under sterile conditions

• Storage: 2–8 °C; protect from light; do not freeze

Suggested Research Protocol (Preclinical Settings Only)

• Administration Route: Subcutaneous (SC) or intramuscular (IM)

• Starting Dose Range: 10–25 mg/day

• Frequency: Daily or every other day, depending on research design

• Half-life: ~24 hours, supporting once-daily dosing in most protocols

Note: Dosage and protocol should be determined by institutional animal care and use committees (IACUC) or other ethical boards as appropriate.

Bioavailability & Kinetics

• Injectable Form Advantage:

  • Increased systemic bioavailability (~90–100%) compared to oral (~60–70%)

  • Rapid onset of action; GH elevation detectable within hours

  • Avoids first-pass hepatic metabolism

Observed Side Effects in Animal and Clinical Models

• Metabolic Effects:

  • Increased appetite

  • Mild to moderate fluid retention

  • Insulin sensitivity changes; monitor glucose levels

• Neuromuscular:

  • Transient muscle/joint discomfort

  • Numbness or tingling in extremities (dose-dependent)

• General:

  • Lethargy or somnolence

⚠️ Contraindicated in research involving cancer models where IGF-1 modulation may confound results.

Handling & Safety Protocols

• Handle in sterile conditions using aseptic technique

• Use appropriate PPE: gloves, lab coat, and protective eyewear

• Dispose of all sharps and biologically contaminated materials in accordance with institutional biohazard protocols

• For research personnel only – keep out of reach of unauthorized personnel

Regulatory Disclaimer

This compound is sold for laboratory and research use only. It is not intended for human ingestion, diagnosis, therapeutic intervention, or clinical trials.

• Not approved by the U.S. Food and Drug Administration (FDA)

• Use is restricted to qualified personnel in licensed research facilities

• Any off-label or non-compliant use is strictly prohibited

Relevant Literature & References

• Nass R, Pezzoli SS, Oliveri MC, Patrie JT, Harrell FE, Clasey JL, Heymsfield SB, Thorner MO. “Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults.” Ann Intern Med.

• Smith RG, et al. “Development of MK-677, a novel growth hormone secretagogue.” J Clin Endocrinol Metab.

• ClinicalTrials.gov identifiers for Ibutamoren: [NCT01020843], [NCT01372644]