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 Do not publish dosing, sourcing, or treatment instructions.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.

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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.

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