Identity
MK-677, or ibutamoren, is an oral small-molecule ghrelin mimetic, not a peptide.
Selected study only; not a complete clinical review.
Peptide library
MK-677 (Ibutamoren)
Your guide to this compound.
Mechanism illustrationEnlarge
Evidence in perspective
The randomized older-adult trial increased fat-free mass without improving strength or function. The clinically meaningful endpoint distinction matters; a change in body composition is not proof of healthier aging.
About this assessment
Existing source snapshot critically reassessed.
Based on the selected source scope described in this profile, often an indexed abstract. Full methods and clinician sign-off remain pending; no systematic-review claim.
Editorial assessment · 2026-09-07
Who was studied
65 healthy adults aged 60–81; randomized placebo-controlled trial.
What the sources found
Fat-free mass increased without improved strength or function. Visceral fat did not significantly decrease.
Regulatory scope
Current authorization for the exact product and jurisdiction was not independently checked in this snapshot. A clinical trial is not marketing authorization.
What remains unknown
Selected indexed primary-study abstract reviewed. Full methods, bias, all safety outcomes, product stability, current jurisdictional authorization and a comprehensive literature search remain outstanding. This is not a complete clinical review.
How it works
MK-677, or ibutamoren, is an oral small-molecule ghrelin mimetic, not a peptide.
The study-specific findings below distinguish biological activity from demonstrated treatment benefit.
Human trials
This catalog identifies human research. A trial can be early, small or negative; its existence does not establish approval or benefit for every proposed use. Check the study population and outcomes.
Reported adverse effects
- Fasting glucose increased and insulin sensitivity declined; appetite, edema and muscle pain were reported.
Selected study only; not a complete clinical review.
Contraindications
- A complete contraindication and interaction review remains outstanding.
Human trials
This catalog identifies human research. A trial can be early, small or negative; its existence does not establish approval or benefit for every proposed use. Check the study population and outcomes.
Sources used for this snapshot
Claim-by-claim evidence
Benefits
Fat-free mass increased without improved strength or function. Visceral fat did not significantly decrease.
Selected study only; not a complete clinical review.
Adverseeffects
Fasting glucose increased and insulin sensitivity declined; appetite, edema and muscle pain were reported.
Selected study only; not a complete clinical review.
References
Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. 2008.
PMID: 18981485
Catalog review date: Sep 7, 2026. This date alone does not establish independent clinical review.