MK-677 (Ibutamoren)
Also sold as Ibutamoren, Nutrobal.
- Half-life
- 24 h
- Steady state
- ~5 d
- Class
- GH (Oral)
- Category
- Peptide
Published population averages. Steady state is the usual five half-life rule of thumb, not a measurement. See peptide half-life, explained.
Overview
MK-677 (Ibutamoren) is a non-peptide oral growth hormone secretagogue that mimics ghrelin signaling to stimulate sustained GH and IGF-1 elevation. Unlike injectable GH peptides, it is orally bioavailable and produces 24-hour GH elevation from a single daily dose. It has been studied for muscle wasting, bone density, sleep quality, and aging.
How it works
Agonizes the ghrelin receptor (GHSR1a) in the hypothalamus and pituitary, stimulating endogenous GH release while preserving pulsatility. Increases IGF-1 levels by 40–60% within weeks. Also increases appetite via ghrelin pathway activation. Does not suppress the HPG axis or affect cortisol. Insulin sensitivity may decrease slightly with chronic use.
Half-life and peak
Oral half-life is approximately 24 hours, supporting once-daily dosing. Peak plasma concentration reached in 1–2 hours. GH pulses are amplified for the full 24-hour period. IGF-1 elevation is sustained and cumulative, reaching maximal levels in 2–4 weeks.
What it is studied for
GH deficiency, sarcopenia in elderly, bone density improvement, sleep architecture (deep sleep enhancement), nitrogen balance in catabolic states, longevity protocols.
Research status
Phase 2 trials completed for multiple indications. Not FDA-approved (development discontinued by Merck). Widely available in anti-aging medicine. Long-term (2-year) safety data available from elderly studies.
Sources
- MK-677 in elderly — Annals of Internal Medicine · pubmed.ncbi.nlm.nih.gov
- MK-677 and sleep quality — Neuroendocrinology · doi.org
- MK-677 bone mineral density — J. Clin. Endocrinol. · doi.org
- MK-677 pharmacokinetics — J. Clin. Pharmacol. · doi.org
Educational reference only. This page describes what is published about a compound; it is not medical advice, not a recommendation to take anything, and not a dosing guide. Several compounds in this catalog are investigational and are not approved medicines. Talk to a doctor.