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 2026-07-01 Next review 2026-07-29

Evidence snapshot

Track clinical trial history and community claims. Do not publish dosing, sourcing, or treatment instructions. Flag the gap between published Phase 2 data and the absence of FDA approval or continued development.

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.

Tracked claims

MK-677 is widely sold online as a 'research chemical' despite having clinical trial data.

Evidence level: Community discussion

Sources: U.S. Food and Drug Administration

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.

Sources on this page

Source records are stored in the repo and linked from each claim.

Oral Ghrelin Mimetic MK-677 Stimulates Pulsatile GH Secretion

Journal of Clinical Endocrinology & Metabolism (PubMed) · Peer reviewed · 2000-02-01 · accessed 2026-07-01

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.

A 12-Month Study of the GH-Releasing Compound MK-677 in Hip Fracture Recovery

Journal of the American Geriatrics Society (PubMed) · Peer reviewed · 2002-03-01 · accessed 2026-07-01

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.

MK-677 Hip Fracture Recovery Trial — ClinicalTrials.gov

ClinicalTrials.gov / U.S. National Library of Medicine · Primary regulatory · 2009-11-01 · accessed 2026-07-01

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.

Warning Letter: Gram Peptides

U.S. Food and Drug Administration · Primary regulatory · 2026-03-31 · accessed 2026-06-30

FDA warning letter discussing peptide products marketed online and the limits of research-use-only positioning.