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Ghrelin receptor agonist (peptidomimetic)

Macimorelin

Macimorelin is an orally active ghrelin/growth hormone secretagogue receptor agonist.

By The Peptides Codex Editorial TeamIndividual review date not recorded

Page data last changed: . Chemistry registry snapshot: . Registry refreshes and identity assessments are separate from scientific content review.

Length
n/a
Class
Ghrelin receptor agonist (peptidomimetic)
Function
Growth hormone secretagogue receptor agonist
Context
FDA-approved oral diagnostic agent for adult growth hormone deficiency (prescription)

First oral, ghrelin-mimetic diagnostic test for adult growth hormone deficiency.

Also known as: Macrilen · AEZS-130 · ghrelin receptor agonist

Part of the Growth hormone & IGF peptides cluster

Overview

Macimorelin is an orally active ghrelin/growth hormone secretagogue receptor agonist. It was approved by the FDA in 2017 as a diagnostic agent that stimulates growth hormone release to help evaluate adult growth hormone deficiency. This page is educational and is not medical advice.

Source & context

Biological / chemical source: Synthetic orally active peptidomimetic

Primary research or clinical context: FDA-approved oral diagnostic agent for adult growth hormone deficiency (prescription)

A diagnostic, not a treatment

Macimorelin is used to provoke a measurable growth hormone response. Because it is taken by mouth, it offers a simpler alternative to older stimulation tests such as the insulin tolerance test for assessing adult GH deficiency.

Ghrelin-mimetic action

By activating the growth hormone secretagogue receptor, macimorelin mimics ghrelin's ability to trigger pituitary GH release. This links it conceptually to research GH secretagogues such as ipamorelin and the GHRP family.

Structure & chemistry

Molecular identity & reference confidence

Source-supported reference

Reference values are taken from the cited molecular record or curated profile. A database match is not independent laboratory verification; modifications, counter-ions, and formulations can change the measured mass.

Molecular form
Macimorelin (source record; form not independently established)
Species
Not established by this molecular identity audit
Termini (N / C)
Not specified / Not specified

Average reference mass

Reference policy updated: 2026-10-05

Molecular formula
C26H30N6O3
Average reference mass
≈ 474.6
Status
Approved medicine in at least one jurisdiction (IUPHAR record)
Identifiers

Chemistry values: PubChem, IUPHAR/BPS Guide to Pharmacology · fetched 2026-10-01.

Clinical development snapshot

ClinicalTrials.gov lists 6 registered studies with “Macimorelin” as an intervention (snapshot 2026-09-06). A registry footprint is not evidence of efficacy or approval.

Registered studies
6
Highest phase reached
Phase 3
Active in latest 100
0
Most recent update
2024-08-12
Most recently updated studies
NCTTitlePhaseStatusUpdated
NCT04786873A Research Study of How Well Macimorelin Works to Find Out if Children Have a Lack of Growth Hormone and How SPhase 3completed2024-08-12
NCT01614990Pilot Clinical Trial of Repeated Doses of Macimorelin to Assess Safety and Efficacy in Patients With Cancer CaPhase 2completed2024-03-20
NCT03844217Copeptin After an Oral Stimulation With Macimorelin in Healthy VolunteersNot applicablecompleted2019-08-08
NCT00448747Investigation of a New, Oral Growth Hormone Secretagogue, AEZS-130 as a Growth Hormone Stimulation Test.Phase 3completed2019-07-23
NCT02558829Validation of Macimorelin as a Test for Adult Growth Hormone DeficiencyPhase 3completed2018-04-10
NCT00377377Oral Ghrelin Agonist in Healthy SubjectsPhase 1completed2007-05-03
See all on ClinicalTrials.gov →
Concentration math

Macimorelin — reconstitution calculator

Enter how much peptide is in the vial and how much diluent (e.g. bacteriostatic water) is added. The tool returns the resulting solution concentration — and, for any amount you type, the volume it corresponds to. This is educational arithmetic, not a dosing recommendation.

Reference form: Macimorelin (source record; form not independently established)Average reference mass: 474.6 Da

Syringe graduation
Solution concentration
5 mg/mL5,000 mcg/mL
mcg

Enter an amount to see the volume it corresponds to.

Educational concentration mathematics only. This tool does not recommend a dose, amount, or protocol, and nothing here is medical advice. Many peptides are not authorized by Health Canada for human use — see our reconstitution and bacteriostatic-water guides for context.

Open the Macimorelin calculator on its own page →

FAQ about Macimorelin

What is Macimorelin?+

Macimorelin is an orally active ghrelin/growth hormone secretagogue receptor agonist. It was approved by the FDA in 2017 as a diagnostic agent that stimulates growth hormone release to help evaluate adult growth hormone deficiency. This page is educational and is not medical advice.

What Canadian product status is recorded for Macimorelin?+

Canadian product status for Macimorelin has not been verified in this profile. No verified record here does not mean no authorization exists. Status depends on the product, formulation and use; consult Health Canada's product records.

What is the typical length of Macimorelin?+

Macimorelin is not a classic amino-acid chain peptide in the same sense; see the profile for classification details.

Related peptides

Motilin
Gut hormone
Motilin is a 22-amino-acid gut hormone secreted by endocrine cells of the small intestine. It coordinates the migrating motor complex, the wave of contractions that clears the digestive tract between meals, earning it the nickname the housekeeper of the gut.
Obestatin
Gut hormone
Obestatin is a 23-amino-acid peptide cleaved from the same preproghrelin precursor that produces ghrelin. It was originally proposed to oppose ghrelin's appetite-stimulating effects, though its physiology and receptor remain actively debated in the research literature.
Albiglutide
Incretin mimetic (GLP-1 receptor agonist)
Albiglutide is a GLP-1 receptor agonist created by genetically fusing two modified GLP-1 sequences to human serum albumin, giving it a long half-life suited to once-weekly dosing. Approved as Tanzeum and Eperzan in 2014, it was later withdrawn from the market for commercial reasons and is now a historical case study.
Neurotensin
Neuropeptide
Neurotensin is a 13-amino-acid neuropeptide found in the brain and gut. Research examines its interactions with dopamine signaling and its roles as a neuromodulator and local hormone.

References & further reading

  1. 1.Henry (2022). Macimorelin Acetate for the Diagnosis of Childhood-onset Growth Hormone Deficiency. touchREV Endocrinol
  2. 2.Garcia et al. (2018). Macimorelin as a Diagnostic Test for Adult GH Deficiency. J Clin Endocrinol Metab
  3. 3.Garcia et al. (2013). Macimorelin (AEZS-130)-stimulated growth hormone (GH) test: validation of a novel oral stimulation test for the diagnosis of adult GH deficiency. J Clin Endocrinol Metab
  4. 4.Yadav et al. (2026). Real-world diagnostic performance of the macimorelin stimulation test in the diagnosis of adult growth hormone deficiency. Pituitary
  5. 5.Herodes et al. (2023). Pilot clinical trial of macimorelin to assess safety and efficacy in patients with cancer cachexia. J Cachexia Sarcopenia Muscle
  6. 6.Lissy et al. (2021). Thorough QT/QTc Study Evaluating the Effect of Macimorelin on Cardiac Safety Parameters in Healthy Participants. Clin Pharmacol Drug Dev
  7. 7.Wang et al. (2025). Molecular recognition of two approved drugs Macimorelin and Anamorelin by the growth hormone secretagogue receptor. Acta Pharmacol Sin
  8. 8.Garcia et al. (2021). Sensitivity and specificity of the macimorelin test for diagnosis of AGHD. Endocr Connect
  9. 9.PubChem — compound summary for Macimorelin (CID 9804938)
  10. 10.Wikipedia — Macimorelin
Disclaimer: Educational content only. Not medical advice. Not instructions for human use. Research peptides and unapproved products may be restricted or illegal to market for human consumption in your jurisdiction. Consult qualified professionals and applicable law.
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