MK-677 (ibutamoren)
MK-677 (ibutamoren)
Evidence & Status
- Moderate Evidence
- Moderate
At a Glance
A non-peptide, orally active small-molecule ghrelin-receptor agonist with bounded human GH/IGF-1 biomarker and body-composition findings. It remains investigational and is not FDA-approved.
Plain English
Researchers study MK-677 as an oral small-molecule ghrelin-receptor agonist, not as a peptide. Defined-population trials report bounded biomarker and body-composition findings, but the hip-fracture trial did not establish its targeted functional benefit and the evidence does not establish a validated therapy or longevity benefit.
Overview
Ibutamoren (MK-677) is an orally active, non-peptide small-molecule ghrelin-receptor agonist; it is not a peptide. The approved clinical sources evaluate specific populations and outcomes, including growth-hormone-deficient children, older adults, hip-fracture patients, and hemodialysis patients. It is not FDA-approved.
Research Summary
The retained trials show bounded human GH/IGF-1 biomarker and body-composition findings in defined populations. The hip-fracture trial did not establish its targeted functional benefit. These results do not establish benefit for healthy-person performance, longevity, or an off-label regimen. Current sport status must be checked against the live WADA Prohibited List.
Research Areas
- Growth hormone deficiency
- Lean muscle mass
- Bone mineral density
- Sleep architecture
- IGF-1 axis modulation
- Sarcopenia
Safety & Risks
Serious Risks
- Fasting-glucose increase and reduced insulin sensitivity in supported human findings.
- Edema/fluid retention in supported human findings.
Reported Side Effects
- Increased appetite
- Edema/fluid retention
- Elevated fasting glucose
- Reduced insulin sensitivity
Legal Status by Region
- United States
- Investigational; not FDA-approved.
- United Kingdom
- Investigational; not FDA-approved.
- Australia
- Investigational; not FDA-approved.
- Canada
- Investigational; not FDA-approved.
Citations & Sources
- 2026 Prohibited List.
World Anti-Doping Agency · 2026
- Effects of oral administration of ibutamoren mesylate, a nonpeptide growth hormone secretagogue, on the growth hormone-insulin-like growth factor I axis in growth hormone-deficient children.
Codner E et al. · Clinical Pharmacology & Therapeutics · 2001
PMID 11452249 · DOI 10.1067/mcp.2001.116514
- Treatment with the oral growth hormone secretagogue MK-677 increases markers of bone formation and bone resorption in obese young males.
Svensson J et al. · Journal of Bone and Mineral Research · 1998
PMID 9661080 · DOI 10.1359/jbmr.1998.13.7.1158
- The effects of MK-0677, an oral growth hormone secretagogue, in patients with hip fracture.
Bach MA et al. · Journal of the American Geriatrics Society · 2004
PMID 15066065 · DOI 10.1111/j.1532-5415.2004.52156.x
- Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial.
Nass R et al. · Annals of Internal Medicine · 2008
PMID 18981485 · DOI 10.7326/0003-4819-149-9-200811040-00003
- Growth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial.
Sevigny JJ et al. · Neurology · 2008
PMID 19015485 · DOI 10.1212/01.wnl.0000335163.88054.e7
- Oral ghrelin receptor agonist MK-0677 increases serum insulin-like growth factor 1 in hemodialysis patients: a randomized blinded study.
Campbell GA et al. · Nephrology Dialysis Transplantation · 2018
PMID 28340044 · DOI 10.1093/ndt/gfw474