Reviewed by Peptide Treatments Medical Advisory Board (Medical Advisory Board)

MK-677: Evidence Summary

Evidence summary for MK-677 across studied indications. Each indication is graded using our evidence tier system based on the quality and quantity of available clinical data.

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Indication Evidence Tier Trial Count Summary
Growth hormone secretion Tier B 6 Consistently raises GH and IGF-1 levels to youthful ranges in clinical trials
Muscle wasting / sarcopenia Tier C 3 Improved lean mass in elderly subjects but mixed functional outcomes
Sleep quality Tier C 2 Increased REM and stage IV sleep duration in healthy volunteers

References (10)

  1. MK-677 Phase 1: Increased GH and IGF-1. . Journal of Clinical Endocrinology & Metabolism (1995) PMID: 9329386
  2. MK-677 in GH deficient adults. . Journal of Clinical Endocrinology & Metabolism (1997) PMID: 18981485
  3. MK-677 in elderly: Increased GH, lean mass. . Annals of Internal Medicine (2001)
  4. MK-677 in cachexia: Increased appetite and weight. . Journal of Clinical Endocrinology & Metabolism (2008)
  5. Design, Biological Characterization, and Discovery of Capromorelin Derivatives as Oral Growth Hormone Secretagogue Receptor Type 1a Agonist for the Treatment of Growth Hormone Deficiency. . Journal of medicinal chemistry (2025) PMID: 40091212
  6. Investigating the P53-dependent anti-cancer effect of ibutamoren in human cancer cell lines. . Basic & clinical pharmacology & toxicology (2025) PMID: 39668330
  7. Structural basis of human ghrelin receptor signaling by ghrelin and the synthetic agonist ibutamoren. . Nature communications (2021) PMID: 34737341
  8. LGD-4033 and MK-677 use impacts body composition, circulating biomarkers, and skeletal muscle androgenic hormone and receptor content: A case report. . Experimental physiology (2022) PMID: 36303408
  9. Beyond the androgen receptor: the role of growth hormone secretagogues in the modern management of body composition in hypogonadal males. . Translational andrology and urology (2020) PMID: 32257855
  10. Reversible Gynecomastia and Hypogonadism Due to Usage of Commercial Performance-Enhancing Supplement Use. . JCEM case reports (2024) PMID: 39145153