MK-677 (Ibutamoren)
Ibutamoren · MK677 · MK 677 · Nutrobal
Orally active growth hormone secretagogue (ghrelin receptor agonist) that elevates GH and IGF-1; the non-peptide counterpart to injectable GHRPs.
Overview
MK-677 (ibutamoren) is an orally active, non-peptide growth hormone secretagogue that mimics ghrelin at the GHS-R1a receptor to elevate growth hormone and IGF-1 levels. Unlike the injectable GHRPs, it is taken by mouth, which is a large part of its appeal. Its half-life is roughly five hours with around 60% bioavailability, which in research contexts supports once-daily dosing. MK-677 actually has a deeper human evidence base than most compounds on this list, with multiple Phase 2 trials examining it for frailty, osteoporosis, and growth hormone deficiency. It did not gain approval, and long-term safety data remains limited. Common effects include increased appetite, transient water retention, and elevated fasting blood glucose, so the risk profile is real and worth tracking.
Pharmacokinetic summary
- Model tier
- Simple (t½ + F, Tmax estimated)
- Half-life
- 0.2 days
- Bioavailability
- 60%
- Typical dose
- 10–25 mg
Related compounds
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