MK-677
Ghrelin Receptor Agonist | Growth Hormone Secretagogue
MK-677 (Ibutamoren) is a selective ghrelin receptor agonist that stimulates growth hormone release without suppressing natural production. This orally active compound increases IGF-1 levels, improves sleep quality, and supports body composition changes through sustained growth hormone elevation.
Daily dose
25mg
Frequency
1x daily
Cycle length
8-12 weeks
Storage
Room temp
Key benefits
97% increase in 24-hour growth hormone secretion, 40-72% IGF-1 elevation, improved sleep quality, enhanced body composition without suppressing natural GH production.
How it works
MK-677 selectively binds ghrelin receptors to stimulate pulsatile growth hormone release while preserving natural circadian patterns. Superior oral bioavailability >60% enables convenient once-daily dosing.
Dosage protocols
Goal
Body composition/Anti-aging
Dose
25mg · 1x daily
Route
Oral (bedtime)
Goal
Sleep improvement
Dose
25mg · 1x nightly
Route
Oral (before bed)
Goal
Conservative start
Dose
12.5mg · 1x daily
Route
Oral (assess tolerance)
Research indications
tissue Repair
anti Aging
energy Metabolism
Administration
Interactions
Safety notes
FDA warns of significant cardiovascular risks including heart failure potential
Contraindicated in heart disease, diabetes, active cancer
Decreases insulin sensitivity - monitor blood glucose
Requires medical supervision and regular monitoring
Not FDA approved - investigational drug status only
Research studies
Hip Fracture Recovery Trial - Terminated (2011)
Elderly patients | 25mg oral daily | Study terminated early | Safety concerns - heart failure risk
Adunsky et al. study was terminated due to increased heart failure incidence in elderly patients, establishing critical safety limitations and contraindications for cardiovascular disease.
View study →Bone Turnover Markers Study (1999)
Elderly adults | 25mg oral daily | 2 months | 39-45% increase in bone formation markers
Murphy et al. showed MK-677 increased bone turnover markers including osteocalcin, suggesting potential benefits for bone health through growth hormone axis activation.
View study →Body Composition in Obese Subjects (1998)
Obese adults | 25mg oral daily | 2 months | Increased fat-free mass and energy expenditure
Svensson et al. showed MK-677 increased growth hormone secretion, fat-free mass, and energy expenditure in obese subjects while maintaining effects throughout treatment duration.
View study →Reversal of Diet-Induced Catabolism (1998)
Healthy adults | 25mg oral daily | 7 days | +2.69g/day nitrogen retention vs -8.97g/day placebo
Murphy et al. demonstrated MK-677's anti-catabolic effects, showing significant nitrogen retention and muscle preservation during caloric restriction compared to placebo.
View study →Sleep Quality Improvement Study (1997)
Young and elderly adults | 25mg oral daily | 1 week | 20% REM increase in young, 50% in elderly
Copinschi et al. demonstrated significant sleep quality improvements with MK-677, particularly REM sleep enhancement that contributes to recovery and growth hormone optimization.
View study →Growth Hormone Stimulation in Elderly (1996)
Elderly adults | 25mg oral daily | 2 weeks | 97% increase in 24-hour GH secretion
Chapman et al. demonstrated MK-677's ability to restore youthful growth hormone levels in elderly subjects, with sustained elevation maintained without tachyphylaxis over extended treatment periods.
View study →