Ibutamoren mesylate (MK-677)

Description

Ibutamoren Mesylate (MK-677) is a high-purity, research-grade non-peptide growth hormone secretagogue supplied as a white to off-white powder or in capsule/tablet form (commonly 10mg, 12.5mg, or 25mg per unit in research products). This compound is intended exclusively for laboratory and scientific research purposes, including in vitro studies, animal models, neuroendocrine assays, or investigations into growth hormone (GH) and IGF-1 axis regulation, metabolism, appetite, and aging-related processes. Ibutamoren (MK-677) is not approved for human consumption, therapeutic use, medical treatment, performance enhancement, or veterinary applications by any regulatory agency (e.g., FDA, EMA). All handling must be performed by qualified researchers following strict laboratory and biosafety protocols.

Key Specifications

• Chemical Name: Ibutamoren mesylate / (2-Amino-N-[(1R)-1-(1,3-benzodioxol-5-yl)-2-(methylsulfonyl)ethyl]-2-methylpropanamide methanesulfonate)
• Molecular Formula: C₂₇H₃₆N₄O₅S · CH₄O₃S (free base: C₂₇H₃₆N₄O₅S)
• Molecular Weight: Free base ≈ 528.66 g/mol; Mesylate salt ≈ 624.77 g/mol
• CAS Number: 159752-10-0 (free base); 178261-41-1 (mesylate salt)
• Synonyms: MK-677, MK677, Nutrobal
• Purity: ≥98–99% (verified by HPLC; third-party Certificate of Analysis recommended)
• Appearance: White to off-white crystalline powder (or encapsulated/tableted in research products)
• Solubility: Soluble in DMSO, ethanol, and water (mesylate form improves aqueous solubility)
• Storage: Store in a cool, dry place away from light and moisture; refrigerate or freeze for long-term stability. Protect from humidity.

Research Background and Mechanism

Ibutamoren (MK-677) is an orally active, non-peptide agonist of the ghrelin receptor (GHS-R1a/growth hormone secretagogue receptor). Developed in the 1990s by Merck & Co., it mimics the action of endogenous ghrelin to stimulate pulsatile release of growth hormone (GH) from the pituitary gland without directly affecting other pituitary hormones significantly (e.g., minimal impact on prolactin or cortisol in most models). Unlike injectable GHRPs or GHRH analogs, MK-677 is orally bioavailable and produces sustained elevation of GH and IGF-1 levels over 24 hours due to its long half-life (~24 hours).

Key mechanisms explored in preclinical and early clinical research models include:

• Stimulation of GH secretion via GHS-R1a activation → increased intracellular calcium and GH release
• Elevation of circulating IGF-1 levels (often 40–80% above baseline in studies)
• Increased appetite and food intake (ghrelin-like effect on hypothalamic feeding centers)
• Potential improvement in nitrogen balance, lean body mass, and bone mineral density in catabolic or aging models
• Modulation of sleep architecture (increased REM and slow-wave sleep in some studies)
• Possible effects on insulin sensitivity and glucose metabolism (mixed results in models)

Animal studies (rats, dogs) and early human trials (1990s–2000s) demonstrated sustained GH/IGF-1 elevation, increased fat-free mass, and appetite stimulation without tachyphylaxis (loss of effect) over weeks to months.

Potential Research Applications

In controlled laboratory settings, Ibutamoren (MK-677) is investigated for:

• GH/IGF-1 axis regulation and long-term pulsatile secretion patterns
• Appetite regulation and energy homeostasis via ghrelin signaling
• Metabolic studies (body composition, nitrogen retention, lipolysis in models)
• Age-related decline in GH/IGF-1 and sarcopenia/osteopenia models
• Sleep physiology and circadian rhythm influences
• Recovery, tissue maintenance, and anabolic/catabolic balance in stress or deficiency models

Its oral bioavailability and sustained action make it a unique tool for studying chronic GH elevation compared to short-acting peptides.

Important Notes

Ibutamoren (MK-677) remains unapproved for any human or clinical use. Development as a therapeutic (e.g., for GH deficiency, frailty, or muscle wasting) was discontinued by Merck after Phase II trials showed mixed efficacy and concerns (e.g., increased fasting glucose, mild edema). No modern regulatory approval exists for any indication. All products are sold strictly for research use only — not for diagnostic, therapeutic, personal consumption, or performance enhancement purposes. Researchers must use accurate dosing, proper storage, and biosafety measures. Always verify purity and identity via independent lab analysis (COA) and comply with institutional guidelines.