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MK-677 (Ibutamoren)
Research Use
Also known as Nutrobal, MK-0677
Function
Primary
GH/IGF-1 elevation · Body composition
Secondary
Bone density · Sleep quality
Mechanism
Oral ghrelin mimetic / GHS-R1a agonist — selectively stimulates GH and IGF-1; oral bioavailability; increases REM sleep.
Evidence
Pre-clinical / Observational
Research
Phase II/III completed; not submitted for approval
Dosing
Range
10–25 mg/day
Frequency
Once daily (evening)
Route
Oral
Cycling
8–12 weeks on / 4 weeks off; monitor IGF-1 and glucose.
Benefits
- ·Sustained IGF-1 elevation
- ·Oral dosing convenience
- ·Improved sleep depth
Risks
- ·Insulin resistance
- ·Water retention
- ·Increased appetite
- ·Lethargy
- ·IGF-1 oncogenicity concern
Contraindications
- ·Type 2 diabetes (caution)
- ·Active malignancy
- ·Heart failure
- ·Pregnancy
Regulatory
Not FDA-approved; investigational IND (Merck)
Functional Groups
Cited Works
- Nass R et al. Effects of an oral ghrelin mimetic on body composition. Ann Intern Med. 2008;149:601.source