MK-677 (Ibutamoren): research summary
An orally-active growth hormone secretagogue that mimics ghrelin signalling. Here's what the current research literature says about its effects on GH/IGF-1, sleep, and body composition.
Overview
MK-677 (Ibutamoren) is a non-peptide, orally-active growth hormone secretagogue. Unlike injected peptides in the same category, it is bioavailable via oral administration, which has made it popular in longer-running research protocols where injection fatigue is a practical concern.
Mechanism
MK-677 acts as a ghrelin mimetic, binding to and activating the growth hormone secretagogue receptor (GHSR). Activation of GHSR stimulates pulsatile GH release from the pituitary, which in turn drives hepatic IGF-1 production.
What research examines
- Pulsatile GH release and 24-hour IGF-1 levels
- Lean mass changes in older adult cohorts
- Sleep architecture, particularly slow-wave sleep
- Appetite modulation via ghrelin signalling