What it is
Ibutamoren (MK-677) is an orally available ghrelin mimetic and growth hormone secretagogue (GHSR-1a agonist). Unlike injectable GHRPs, it is taken by mouth and has a long half-life, which makes once-daily oral dosing practical — at the cost of a less controllable pulse profile than injectable secretagogues.
Evidence boundary
Extensive clinical study history (long GH/IGF-1 elevation trials); research use is limited to laboratory and education contexts.
Trial evidence
- Ibutamoren has been studied in long-term human trials for GH/IGF-1 elevation, including effects on lean body mass and sleep quality.
Preparation and measurement
Oral dosing — no reconstitution. Measure by weight with a precision scale.
Concentration matches.
Reference schedule
| Phase | Dose | Draw / measure | Frequency | Weekly total |
|---|---|---|---|---|
| Conservative start | 10 mg | Oral | Once daily | 70 mg/week |
| Standard research | 15 mg | Oral | Once daily | 105 mg/week |
| Common protocol | 20 mg | Oral | Once daily | 140 mg/week |
| High end | 25 mg | Oral | Once daily | 175 mg/week |
Conservative start
- Dose
- 10 mg
- Draw / measure
- Oral
- Frequency
- Once daily
- Weekly total
- 70 mg/week
Standard research
- Dose
- 15 mg
- Draw / measure
- Oral
- Frequency
- Once daily
- Weekly total
- 105 mg/week
Common protocol
- Dose
- 20 mg
- Draw / measure
- Oral
- Frequency
- Once daily
- Weekly total
- 140 mg/week
High end
- Dose
- 25 mg
- Draw / measure
- Oral
- Frequency
- Once daily
- Weekly total
- 175 mg/week
Weekly totals apply only during the active phase.
Titration rules
- Standard research range: 10–25 mg once daily, taken at the same time each day.
- Many protocols take it in the evening, closer to the natural GH pulse.
- Cycles commonly run 8–16 weeks with off periods of similar length.
- Monitor glucose/fasting insulin in longer protocols — insulin sensitivity changes are the most frequently discussed side effect.
- No injection, no BAC, no syringe math — an oral powder measured by weight.