MK-677 (25 mg – 60 Capsules)

MK-677 (Ibutamoren) - Oral Growth Hormone Secretagogue Research Compound Molecular Profile: MK-677 (Ibutamoren, MK-0677, L-163,191) is a potent, orally-active, non-peptide agonist of the ghrelin receptor (GHS-R1a) with molecular formula C₂₇H₃₆N₄O₅S, molecular weight 528.67 g/mol, and CAS 159752-10-0. Unlike peptide-based GH secretagogues requiring injection, MK-677 demonstrates excellent oral bioavailability (~60%) and a prolonged ~24-hour half-life enabling once-daily dosing. The spiroindoline-based structure mimics ghrelin's GH-stimulating action. Mechanism of Action: MK-677 binds GHS-R1a with high affinity (pKi = 8.14, EC₅₀ = 1.3 nM) activating Gq/11 protein signaling, phospholipase C, and intracellular calcium mobilization. This produces sustained, dose-dependent increases in circulating GH (up to 97%) and IGF-1 while maintaining physiological pulsatile release patterns. Recent cryo-EM structures of human GHSR-Gi complex with ibutamoren have revealed molecular mechanisms of receptor activation. Research Applications: This research-grade compound supports investigation of GHS-R1a receptor pharmacology, growth hormone axis regulation, oral secretagogue development, ghrelin system biology, and metabolic research applications. Product Specifications: - Purity: ≥98% (HPLC verified) - Form: Capsules (25 mg × 60) - Storage: Room temperature, protected from light and moisture - Certificate of Analysis provided Laboratory Use Only: This product is intended strictly for in-vitro research applications. NOT FOR HUMAN CONSUMPTION. Not approved for therapeutic use. Intended for qualified researchers and licensed laboratory facilities only.