Description

MK-677 (Ibutamoren, also known as L-163,191) is a non-peptide oral growth hormone secretagogue that mimics the action of ghrelin and activates the GHS-R1a (growth hormone secretagogue receptor 1a). It is the only orally bioavailable GH secretagogue, providing a convenient alternative to injectable GHRPs (growth hormone releasing peptides) such as GHRP-2 and GHRP-6. MK-677 was developed by Merck and has been evaluated in multiple Phase II human clinical trials for conditions including GH deficiency, muscle wasting, hip fracture recovery, and Alzheimer's disease. It significantly elevates both pulsatile GH secretion and IGF-1 levels, with effects lasting approximately 24 hours from a single dose. Unlike injectable GH, MK-677 stimulates the body's own GH production in a physiological pulsatile pattern, which is considered safer and more natural than exogenous GH administration. The compound has demonstrated improvements in body composition, bone mineral density, and sleep quality in human studies.

Key Characteristics

Investigated Benefits

* Benefits based on preclinical/animal research unless otherwise noted.