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evidence · mechanism · dose
Experimental/Diagnostic GH SecretagogueResearch peptide

Macimorelin

aka Macrilen · AEZS-130

Oral ghrelin agonist used as a diagnostic test for adult GH deficiency.

Educational explainer of a research peptide. Profiles in this section deliberately omit clinical-trial citations, dosing protocols, and purchase links. Not FDA-approved as a supplement; not a recommendation to use.

Overview

Macimorelin is an oral ghrelin receptor agonist approved as a diagnostic agent for adult growth hormone deficiency.

Source
  • Approved pharmaceutical
Forms
  • Oral solution

Mechanism of action

Stimulates a robust, predictable GH pulse used as a stimulation test for adult GHD.

Pathways
  • · GHSR-1a
  • · GH release
Hormones
  • · GH

How it acts on the body

Macimorelin replaces older, less convenient GH stimulation tests (insulin tolerance, GHRH-arginine) with a single oral dose that produces a reproducible GH peak. Failure to reach the threshold confirms adult GHD.

Because dosing is single-shot and diagnostic, chronic safety data and physiologic effects are limited to the test setting.

Hormonal & endocrine impact

How this peptide is reported to shift specific hormones and signaling molecules. Directionality reflects research literature and preclinical models, not clinical prescribing data.

Projected hormonal trajectory
Illustrative curves derived from reported direction of effect. Not measured patient data.

Curves are schematic shapes (sigmoid for increases/decreases, damped oscillation for modulation/stabilization) anchored to a 100% baseline. They communicate direction and tempo of change reported in research literature — not absolute hormone concentrations.

GHIncreases
Single diagnostic pulse.

Effects on the body

Increases
Stimulated GH release for diagnostic testing

Organ system effects

Endocrine

Pituitary somatotrophs.

Digestive / Gut

Mild prokinetic effect at diagnostic dose.

Reported effects

Drawn from preclinical research, anecdote, and small-scale clinical observation. No evidence grades are assigned — most peptides on this page lack rigorous human trials.

  • Oral, single-dose diagnostic
  • Replaces more burdensome tests

Potential side effects

Common
  • · Dysgeusia
  • · Fatigue
  • · Headache
Rare
  • · Diarrhea
Serious
  • · QT prolongation — caution with QT-prolonging drugs

Drug interactions

QT-prolonging agents
Class effect — avoid co-administration.
moderate
Strong CYP3A4 inducers
May reduce macimorelin exposure and invalidate test.
moderate

Pairing context

Often combined with
  • Formal endocrinology evaluation
    Test should be interpreted in clinical context.
Avoid combining with
  • Known long-QT syndrome
    Cardiac risk.
Important. Research peptides described here are not FDA-approved supplements. Supplement Scholar does not endorse, recommend, or link to any source for purchase. Consult a qualified clinician before considering any peptide therapy.