Search ↗

Comparison

Anamorelin vs MK-677

Both are gHRPs & ghrelin mimetics, so the meaningful differences are in kinetics, evidence and regulatory status.

Anamorelin MK-677
Class GHRPs & ghrelin mimetics GHRPs & ghrelin mimetics
Evidence Clinical trials Clinical trials
Human trials ~18 ~22
Half-life ~7 hours ~24 hours
Reported range 50-100 mg 10-25 mg
Frequency Once daily Once daily
Routes Oral Oral
FDA approved No No
Research use only Yes Yes
Banned in sport Yes Yes
Studied for Cancer cachexia, Appetite stimulation, Lean mass preservation Growth hormone elevation, Appetite stimulation, Sleep depth, Lean mass
Reported side effects Hyperglycaemia, Nausea, Elevated hepatic enzymes, Headache Increased appetite, Water retention, Reduced insulin sensitivity, Lethargy, Numbness in extremities

Anamorelin

Anamorelin is a non-peptide small molecule agonist at the growth hormone secretagogue receptor with oral bioavailability, which separates it from the injectable hexapeptides. In phase III cancer-cachexia trials it increased lean body mass and appetite, though it did not consistently improve handgrip strength, which is why its regulatory path diverged between Japan and the US and Europe. Its oral route and long half-life make it pharmacologically closer to MK-677 than to GHRP-2.

MK-677

MK-677 is a spiropiperidine growth hormone secretagogue receptor agonist, not a peptide, though it is almost always discussed alongside them because it targets the same receptor as the GHRPs. Oral bioavailability and a roughly 24-hour half-life produce sustained elevation of GH and IGF-1 from once-daily dosing. The same sustained exposure drives its two characteristic problems: marked appetite increase and a consistent reduction in insulin sensitivity.

Anamorelin vs MK-677: common questions

What is the difference between Anamorelin and MK-677?

Both are gHRPs & ghrelin mimetics. Anamorelin: An orally active ghrelin-receptor agonist approved in Japan for cancer cachexia, and the most clinically advanced compound in the class. MK-677: An orally active, long-acting ghrelin-receptor agonist. Frequently grouped with peptides but chemically a non-peptide small molecule.

Which has stronger evidence, Anamorelin or MK-677?

They sit at the same evidence level: clinical trials. Anamorelin has about 18 human studies and MK-677 about 22.

Are Anamorelin and MK-677 FDA approved?

Neither is FDA approved for any indication.

References

Regulatory and primary sources

  1. PubChem compound record (CID 9828911) ↗ · structure, identifiers, synonyms
  2. WADA Prohibited List ↗ · current year
  3. FDA: Unapproved drugs and "research use only" products ↗ · regulatory status of non-approved products
  4. CAS Registry Number 249921-19-5 ↗ · chemical identity
  5. PubChem compound record (CID 6450830) ↗ · structure, identifiers, synonyms
  6. CAS Registry Number 159752-10-0 ↗ · chemical identity

Published literature

  1. Nishie K, Sato S, Hanaoka M. Anamorelin for cancer cachexia.Drugs Today (Barc) 2022.PubMed 35274629 · doi:10.1358/dot.2022.58.3.3381585
  2. Garcia JM. What is next after anamorelin?.Curr Opin Support Palliat Care 2017.PubMed 28957883 · doi:10.1097/SPC.0000000000000299
  3. Rezaei S, de Oliveira LC, Ghanavati M, et al.. The effect of anamorelin (ONO-7643) on cachexia in cancer patients: Systematic review and meta-analysis of randomized controlled trials.J Oncol Pharm Pract 2023.PubMed 37525932 · doi:10.1177/10781552231189864
  4. Takayama K. [Overview of Cancer-Associated Cachexia].Gan To Kagaku Ryoho 2019.PubMed 31879394
  5. Dev R, Amano K, Naito T, et al.. Anamorelin for the Treatment of Cancer Anorexia-Cachexia Syndrome.Curr Oncol Rep 2024.PubMed 38771469 · doi:10.1007/s11912-024-01549-y
  6. Wakabayashi H, Arai H, Inui A. Anamorelin in Japanese patients with cancer cachexia: an update.Curr Opin Support Palliat Care 2023.PubMed 37389636 · doi:10.1097/SPC.0000000000000658
  7. Crawford J. Clinical results in cachexia therapeutics.Curr Opin Clin Nutr Metab Care 2016.PubMed 26974316 · doi:10.1097/MCO.0000000000000274
  8. Zhang H, Garcia JM. Anamorelin hydrochloride for the treatment of cancer-anorexia-cachexia in NSCLC.Expert Opin Pharmacother 2015.PubMed 25945893 · doi:10.1517/14656566.2015.1041500
  9. Ghigo E, Arvat E, Muccioli G, et al.. Growth hormone-releasing peptides.Eur J Endocrinol 1997.PubMed 9186261 · doi:10.1530/eje.0.1360445
  10. Murphy MG, Plunkett LM, Gertz BJ, et al.. MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism.J Clin Endocrinol Metab 1998.PubMed 9467534 · doi:10.1210/jcem.83.2.4551
  11. Sigalos JT, Pastuszak AW. The Safety and Efficacy of Growth Hormone Secretagogues.Sex Med Rev 2018.PubMed 28400207 · doi:10.1016/j.sxmr.2017.02.004
  12. Camanni F, Ghigo E, Arvat E. Growth hormone-releasing peptides and their analogs.Front Neuroendocrinol 1998.PubMed 9465289 · doi:10.1006/frne.1997.0158
  13. Stawerska R. New directions in growth hormone treatment in children.Pediatr Endocrinol Diabetes Metab 2025.PubMed 41693185 · doi:10.5114/pedm.2025.158544
  14. Muccioli G, Broglio F, Valetto MR, et al.. Growth hormone-releasing peptides and the cardiovascular system.Ann Endocrinol (Paris) 2000.PubMed 10790589
  15. Camiña JP, Carreira MC, Micic D, et al.. Regulation of ghrelin secretion and action.Endocrine 2003.PubMed 14610293 · doi:10.1385/ENDO:22:1:5
  16. Smith RG, Sun Y, Jiang H, et al.. Ghrelin receptor (GHS-R1A) agonists show potential as interventive agents during aging.Ann N Y Acad Sci 2007.PubMed 18056963 · doi:10.1196/annals.1404.023

Literature retrieved from PubMed on October 16, 2026, favouring human studies and reviews. Numbered markers in the text show which paper supports which statement; uncited entries are background reading.

Read this first This page compares published reference data. It is not medical advice and not a recommendation to use either compound. Several compounds documented on this site are not approved for human use.