MK-677 (ibutamoren) is a non-peptide, orally active growth hormone secretagogue developed by Merck that mimics ghrelin to stimulate GH and IGF-1 release. It is not FDA-approved for any indication; Merck discontinued clinical development. Despite multiple published Phase 2 trials showing IGF-1 increases, the compound is sold as a research chemical and is widely discussed in fitness and anti-aging communities.
Oral growth hormone secretagogue (GHS): non-peptide
MK-677 (Ibutamoren)
MK-677 (ibutamoren) is a non-peptide, orally active growth hormone secretagogue developed by Merck that mimics ghrelin to stimulate GH and IGF-1 release. It is not FDA-approved for any indication; Merck discontinued clinical development. Despite multiple published Phase 2 trials showing IGF-1 increases, the compound is sold as a research chemical and is widely discussed in fitness and anti-aging communities.
Evidence review
Last reviewed Jul 1, 2026
Next review Jul 29, 2026
Evidence snapshot
MK-677 is an oral, non-peptide ghrelin receptor agonist (GHS) developed by Merck; multiple Phase 2 trials published in peer-reviewed journals demonstrated sustained increases in IGF-1 levels.
A 12-month Phase 2 study in hip fracture recovery (NCT01016781; PMID 12004295) showed MK-677 improved functional status in elderly patients with hip fracture, but development was not advanced to approval.
A study published in the Journal of Clinical Endocrinology & Metabolism (PMID 10674575) demonstrated that oral MK-677 replicated the pulsatile GH profile seen with intravenous GH secretagogues in healthy older adults.
MK-677 is not FDA-approved for any indication and is widely sold online as a 'research chemical' or 'SARM' despite not being a SARM; FDA warning letters have addressed such marketing.
Research record
What the evidence record says
- Evidence grade
- Not Graded
- Regulatory status
- MK-677 (Ibutamoren) regulatory status has not been fully reviewed by Peptide Report editorial team. See company profiles and regulatory watch for current status.
Evidence records
Studies, registries, reviews, and regulatory records
Evidence review pending
- Detailed evidence review for MK-677 (Ibutamoren) is pending editorial assessment. Current summary reflects available public records.
Records: Oral Ghrelin Mimetic MK-677 Stimulates Pulsatile GH Secretion, A 12-Month Study of the GH-Releasing Compound MK-677 in Hip Fracture Recovery, MK-677 Hip Fracture Recovery Trial: ClinicalTrials.gov
Evidence timeline
What changed, and when
Peptide Report last reviewed MK-677 (Ibutamoren) on 2026-07-01.
Records: Oral Ghrelin Mimetic MK-677 Stimulates Pulsatile GH Secretion
Direct answers
Frequently asked questions
What is MK-677 (Ibutamoren)?
MK-677 (Ibutamoren) is a oral growth hormone secretagogue (ghs): non-peptide tracked by Peptide Report. See the full profile for current editorial assessment.
Open research questions
What is still unknown
- What is the complete human evidence base for MK-677 (Ibutamoren)?
- What are the long-term safety considerations for MK-677 (Ibutamoren)?
Tracked claims
MK-677 increases IGF-1 levels in humans based on published clinical trial data.
Evidence level: Peer reviewed
Sources: Oral Ghrelin Mimetic MK-677 Stimulates Pulsatile GH Secretion, A 12-Month Study of the GH-Releasing Compound MK-677 in Hip Fracture Recovery
How to read this: Cite the published Phase 2 trials directly. IGF-1 increases are a pharmacodynamic marker, not a clinical outcomes claim. Multiple trials showed sustained IGF-1 elevation but no approved indication resulted.
MK-677 is not FDA-approved and Merck discontinued development.
Evidence level: Primary regulatory
Sources: MK-677 Hip Fracture Recovery Trial: ClinicalTrials.gov, Warning Letter: Gram Peptides
How to read this: No FDA approval record exists. Merck (the original developer) did not advance the compound to approval. Products sold as 'research chemicals' are subject to FDA enforcement.
MK-677 is widely sold online as a 'research chemical' despite having clinical trial data.
Evidence level: Community discussion
Sources: Warning Letter: Gram Peptides
How to read this: The research-chemical marketing of MK-677 exists alongside genuine Phase 2 clinical data: this creates a misleading impression of legitimacy. Track the marketing claims and FDA enforcement context.
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Sources on this page
Each source record is linked to the claim or evidence note it supports.
Oral Ghrelin Mimetic MK-677 Stimulates Pulsatile GH Secretion
Svensson et al. (2000) study (PMID 10674575) demonstrating that oral MK-677 replicated the pulsatile GH profile seen with IV secretagogues in healthy older adults, with sustained IGF-1 increases over 4 weeks.
5 linked pagesOpen original ·
pubmed-mk677-gh-profile-2000A 12-Month Study of the GH-Releasing Compound MK-677 in Hip Fracture Recovery
Bach et al. (2002) 12-month Phase 2 trial (PMID 12004295) showing MK-677 improved functional status in elderly patients with hip fracture. Despite positive pharmacodynamic data, Merck did not advance MK-677 to FDA approval.
5 linked pagesOpen original ·
pubmed-mk677-hip-fracture-2002MK-677 Hip Fracture Recovery Trial: ClinicalTrials.gov
ClinicalTrials.gov registry entry (NCT01016781) for the MK-677 hip fracture recovery trial sponsored by Merck. MK-677 is not FDA-approved for any indication.
5 linked pagesOpen original ·
clinicaltrials-gov-mk677-hip-fractureWarning Letter: Gram Peptides
FDA warning letter discussing peptide products marketed online and the limits of research-use-only positioning.
35 linked pagesOpen original ·
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