MK-677 (Ibutamoren)
An orally active growth hormone secretagogue that mimics ghrelin, stimulating sustained GH and IGF-1 release without affecting cortisol.
Common Dosage
10mg - 25mg daily (oral)
Category
Growth Hormone
- Increased GH and IGF-1
- Improved sleep
- Muscle growth
- Bone density support
MK-677 (ibutamoren) was developed by Merck in the 1990s during research into oral growth hormone secretagogues. It is a non-peptide GH secretagogue that mimics ghrelin and was extensively studied in Phase 2 clinical trials for conditions including GH deficiency, osteoporosis, muscle wasting in hip fracture patients, and Alzheimer's disease. While it didn't achieve regulatory approval for any indication, the clinical trial database for MK-677 is substantial — making it one of the better-characterized research compounds used in the self-optimization community.
MK-677 binds to ghrelin receptors (GHS-R1a) and stimulates GH secretion from the pituitary, similar to injectable GHRPs but with oral bioavailability (approximately 60–70%) and a long half-life (~24 hours). It sustainably elevates GH and IGF-1 throughout the day — a different pattern from the pulsatile release produced by injectable GHRPs. It also modulates appetite through its ghrelin-mimetic activity.
- Growth hormone deficiency — clinical trials conducted
- Sarcopenia and muscle wasting in elderly
- Hip fracture recovery — improved rehabilitation outcomes
- Osteoporosis — bone density improvement
- Sleep quality improvement
- Alzheimer's disease — cognitive effects studied
Elderly Sarcopenia Trial
A 12-month clinical trial in elderly hip fracture patients showed that MK-677 significantly improved gait speed, functional activity score, and muscle strength compared to placebo — with sustained IGF-1 elevation throughout. This is among the most clinically meaningful human data for any oral GH secretagogue.
IGF-1 Normalization in Adults
Phase 2 trials consistently demonstrate that MK-677 elevates IGF-1 to youthful range in GH-deficient or normal aging adults, with dose-dependent effects. At 25mg/day, IGF-1 typically reaches the upper range of normal young adult values.
Sleep Enhancement
Double-blind trials have shown increased slow-wave sleep duration and intensity with MK-677, consistent with GH's role in sleep architecture — a particularly valued effect for recovery-focused users.
- Significant appetite increase — difficult to manage in those attempting caloric restriction
- Blood glucose elevation — MK-677 reduces insulin sensitivity; monitoring is important, particularly for pre-diabetics
- Water retention and edema are common, particularly in the first weeks
- Chronic IGF-1 elevation — the proliferative risk concern applies here as with all GH axis peptides
- Numbness and tingling in extremities at higher doses
- Not FDA-approved; oral formulations vary significantly in quality
- Increased appetite
- Water retention
- Numbness
- Blood sugar elevation
Muscle Growth & Performance
Enhancement of lean muscle mass development and recovery from intense training sessions.
Sleep Optimization
Protocols for improving sleep quality, duration, and restorative deep sleep.
Hormonal Balance & Fertility
Support for optimizing hormone levels, reproductive health, and fertility.