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Comparison

Macimorelin vs Sermorelin

Macimorelin is gHRPs & ghrelin mimetics; Sermorelin is GHRH analogs. They are compared here because they are frequently considered against each other, not because they act alike.

Macimorelin Sermorelin
Class GHRPs & ghrelin mimetics GHRH analogs
Evidence Regulator approved Regulator approved
Human trials ~8 ~20
Half-life ~4 hours ~10-20 minutes
Reported range 500 mg 200-500 mcg
Frequency Single 0.5 mg/kg diagnostic dose Once daily at bedtime
Routes Oral Subcutaneous
FDA approved Yes Yes
Research use only No No
Banned in sport Yes Yes
Studied for Diagnosis of adult growth hormone deficiency Growth hormone deficiency diagnosis and paediatric treatment, Age-related GH decline, Sleep quality, Body composition
Reported side effects Dysgeusia, Dizziness, Headache, Fatigue, QT prolongation Injection-site erythema, Flushing, Headache, Transient dizziness

Macimorelin

Macimorelin is an orally active growth hormone secretagogue receptor agonist approved as a single-dose diagnostic test for adult growth hormone deficiency. Administered as an oral solution, it produces a reliable GH rise in subjects with intact pituitary function, so a blunted response identifies deficiency. It replaced the insulin tolerance test in many settings because it avoids induced hypoglycaemia.

Sermorelin

Sermorelin is a truncated analog of growth-hormone-releasing hormone comprising residues 1-29, the minimum sequence required for receptor activation. It binds the GHRH receptor on anterior pituitary somatotrophs and stimulates synthesis and pulsatile release of endogenous growth hormone. Because it acts upstream on the pituitary rather than replacing growth hormone directly, release remains subject to negative feedback from somatostatin and IGF-1, which is the usual argument for a lower risk of supraphysiologic exposure than exogenous hGH.

Macimorelin vs Sermorelin: common questions

What is the difference between Macimorelin and Sermorelin?

Macimorelin is gHRPs & ghrelin mimetics and Sermorelin is GHRH analogs, so they act on different pathways. Macimorelin: An orally administered ghrelin-receptor agonist and the only compound in this class with a current FDA approval. Sermorelin: The first 29 amino acids of endogenous growth-hormone-releasing hormone, and the shortest fragment that retains full biological activity.

Which has stronger evidence, Macimorelin or Sermorelin?

They sit at the same evidence level: regulator approved. Macimorelin has about 8 human studies and Sermorelin about 20.

Are Macimorelin and Sermorelin FDA approved?

Both are FDA approved. Macimorelin: Diagnosis of adult growth hormone deficiency (Macrilen). Sermorelin: Diagnostic assessment of pituitary GH secretory capacity (Geref); Treatment of idiopathic growth hormone deficiency in children with growth failure (Geref, approved 1997; discontinued by the manufacturer in 2008, not for safety reasons).

References

Regulatory and primary sources

  1. PubChem compound record (CID 9804938) ↗ · structure, identifiers, synonyms
  2. DailyMed: FDA-approved labeling for Macimorelin ↗ · indications, dosing, warnings as approved
  3. FDA Drugs@FDA database ↗ · approval history
  4. WADA Prohibited List ↗ · current year
  5. CAS Registry Number 381231-18-1 ↗ · chemical identity
  6. PubChem compound record (CID 16132413) ↗ · structure, identifiers, synonyms
  7. DailyMed: FDA-approved labeling for Sermorelin ↗ · indications, dosing, warnings as approved
  8. FDA Drugs@FDA database ↗ · approval history
  9. CAS Registry Number 86168-78-7 ↗ · chemical identity

Published literature

  1. Refardt J, Atila C, Christ-Crain M. New insights on diagnosis and treatment of AVP deficiency.Rev Endocr Metab Disord 2024.PubMed 38087160 · doi:10.1007/s11154-023-09862-w
  2. Arlien-Søborg MC, Radovick S, Boguszewski MCS, et al.. Consensus and controversies about diagnosing GH deficiency: a Delphi survey by the GH research society.Pituitary 2025.PubMed 40335774 · doi:10.1007/s11102-025-01526-z
  3. Tritos NA. Growth hormone deficiency in adults with Cushing's disease.Best Pract Res Clin Endocrinol Metab 2021.PubMed 33272904 · doi:10.1016/j.beem.2020.101474
  4. Agrawal V, Garcia JM. The macimorelin-stimulated growth hormone test for adult growth hormone deficiency diagnosis.Expert Rev Mol Diagn 2014.PubMed 24834478 · doi:10.1586/14737159.2014.915746
  5. Garcia JM, Biller BMK, Korbonits M, et al.. Macimorelin as a Diagnostic Test for Adult GH Deficiency.J Clin Endocrinol Metab 2018.PubMed 29860473 · doi:10.1210/jc.2018-00665
  6. Tritos NA, Biller BMK. Current concepts of the diagnosis of adult growth hormone deficiency.Rev Endocr Metab Disord 2021.PubMed 32959175 · doi:10.1007/s11154-020-09594-1
  7. Herodes M, Anderson LJ, Shober S, et al.. Pilot clinical trial of macimorelin to assess safety and efficacy in patients with cancer cachexia.J Cachexia Sarcopenia Muscle 2023.PubMed 36860137 · doi:10.1002/jcsm.13191
  8. Cuboni D, Caputo M, Ghigo E, et al.. Once upon a time: the glucagon stimulation test in diagnosing adult GH deficiency.J Endocrinol Invest 2024.PubMed 38461479 · doi:10.1007/s40618-024-02322-5
  9. Rahman OF, Lee SJ, Seeds WA. Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions.J Am Acad Orthop Surg Glob Res Rev 2026.PubMed 41490200 · doi:10.5435/JAAOSGlobal-D-25-00236
  10. Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance.Sports Med 2026.PubMed 41966639 · doi:10.1007/s40279-026-02437-0
  11. Memdouh S, Gavrilović I, Ng K, et al.. Advances in the detection of growth hormone releasing hormone synthetic analogs.Drug Test Anal 2021.PubMed 34665524 · doi:10.1002/dta.3183
  12. Walker RF. Sermorelin: a better approach to management of adult-onset growth hormone insufficiency?.Clin Interv Aging 2006.PubMed 18046908 · doi:10.2147/ciia.2006.1.4.307
  13. Ramirez G, Herrera R, Pineda D, et al.. The effects of high altitude on hypothalamic-pituitary secretory dynamics in men.Clin Endocrinol (Oxf) 1995.PubMed 7641401 · doi:10.1111/j.1365-2265.1995.tb01887.x
  14. Coutinho LFD, DE Oliveira Neves LF, Camilo RP. A new era of doping? Use of peptide and peptide-analog drugs in recreational and professional sport and bodybuilding: a critical review.J Sports Med Phys Fitness 2026.PubMed 41880199 · doi:10.23736/S0022-4707.26.17773-1
  15. Popovic V, Pekic S, Golubicic I, et al.. The impact of cranial irradiation on GH responsiveness to GHRH plus GH-releasing peptide-6.J Clin Endocrinol Metab 2002.PubMed 11994347 · doi:10.1210/jcem.87.5.8485
  16. Saenger P, Pescovitz OH, Bercu BB, et al.. Outcome of growth hormone therapy in children with growth hormone deficiency showing an inadequate response to growth hormone-releasing hormone.Endocrine 2001.PubMed 11572326 · doi:10.1385/ENDO:15:1:051

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.