What Is a Peptide Secretagogue? A Clear Definition

TL;DR

- What is a peptide secretagogue? It is a compound that prompts the body to secrete more of a substance; a growth-hormone secretagogue (GHS) prompts release of the body's own growth hormone. - GHS are commonly grouped into two families by receptor: GHS-R (ghrelin-receptor) agonists and GHRH-receptor agonists. - Ipamorelin is a selective GHS-R agonist studied for growth-hormone release (Raun et al., 1998). - MK-677 (ibutamoren) is an oral ghrelin mimetic; in one trial it raised fasting glucose and lowered insulin sensitivity (Nass et al., 2008). - CJC-1295 is a GHRH analog reported to sustain GH and IGF-1 levels (Teichman et al., 2006).

What is a peptide secretagogue?

A peptide secretagogue is a peptide that signals the body to secrete more of one of its own substances, most often a hormone.

The word "secretagogue" joins "secrete" with the Greek "agogos," meaning "leading" or "promoting." So a secretagogue leads to secretion. Instead of adding a hormone from outside, a secretagogue pushes a gland to release more of what it already makes. In the peptide field, the term most often points to growth-hormone secretagogues (GHS), which act on the pituitary and related pathways to increase growth-hormone (GH) release.

This matters for how a compound is classified. A direct hormone replaces the signal. A secretagogue amplifies the body's own signal, so the release still runs through the body's normal control loops.

How does a growth-hormone secretagogue work?

A growth-hormone secretagogue binds a receptor that tells the pituitary to release stored growth hormone.

Two receptor systems drive GH release, and GHS are generally grouped by which one they hit:

- **GHS-R (ghrelin-receptor) agonists.** These mimic ghrelin, the natural ligand at the growth-hormone secretagogue receptor. Binding this receptor is reported to trigger a pulse of GH. - **GHRH-receptor agonists.** These mimic growth-hormone-releasing hormone (GHRH), the hypothalamic signal that tells the pituitary to make and release GH.

Because both routes work through the pituitary rather than replacing GH directly, output still depends on the body's own feedback signals.

What are the two families of GH secretagogues?

The two families are ghrelin-receptor (GHS-R) agonists and GHRH-receptor agonists, defined by the receptor each targets.

These entries are provided to explain how the compounds are classified in published research, not as guidance to use any of them. Note the evidence column: the ghrelin and GHRH mechanism claims rest on a mix of animal and early human data, so read each row by its own citation.

What are real examples of peptide secretagogues?

Ipamorelin, MK-677, and CJC-1295 are three of the most cited examples, each acting through one of the two receptor families.

**Ipamorelin** is described as a selective GHS-R agonist, meaning it prompts GH release with limited action on other hormones in the preclinical data (Raun et al., 1998).

**MK-677 (ibutamoren)** is an orally active ghrelin mimetic. In a trial in older adults, it acted as a GH secretagogue but also raised fasting glucose and lowered insulin sensitivity (Nass et al., 2008). That side finding is part of why the metabolic profile of oral secretagogues gets close attention.

**CJC-1295** is a GHRH analog. Research reported that it sustained GH and IGF-1 concentrations over an extended window (Teichman et al., 2006).

Human data across this class is uneven. Some compounds have controlled trial data, while others rest largely on preclinical work, so read each example by its own citation rather than assuming the whole class is equally studied.

What research doses have been reported?

Published trials report specific study doses, which are described here only to summarize the research and are not a recommendation.

Any personal dose, schedule, or decision about whether a compound is appropriate belongs with a qualified clinician, not a web page. This section reports what trials studied, nothing more.

How is a secretagogue different from taking the hormone directly?

A secretagogue tells the body to release more of its own hormone, while a direct hormone adds that hormone from outside.

The practical difference is where control sits. With a secretagogue, output still passes through the body's feedback loops at the pituitary, so the natural pulse pattern is closer to preserved. With direct hormone, the external dose sets the level regardless of the body's own signals. This distinction is the main reason the two categories are studied and classified separately.