Growth Hormone Secretagogues Explained

“Secretagogue” sounds technical, but the idea is simple: a compound that prompts a gland to secrete something. In the growth hormone world, a secretagogue is anything that nudges the pituitary to release its own GH rather than supplying GH from outside. This guide sorts the main classes so the naming stops being confusing.

The two families that matter

Almost every GH secretagogue you will encounter belongs to one of two families, defined by which receptor it targets.

1. GHRH analogues

These mimic growth hormone-releasing hormone and bind the GHRH receptor on the pituitary. They amplify the body’s own release signal. Common examples include sermorelin, CJC-1295 and tesamorelin. Within this family, the key variable is duration: sermorelin is short-acting, while CJC-1295 is engineered to last longer. The No DAC form of CJC-1295 keeps a shorter, more pulse-like profile than the albumin-binding DAC form.

2. GHRPs and ghrelin mimetics

These work through a completely different door: the ghrelin receptor (also called the growth hormone secretagogue receptor, GHS-R). This family includes ipamorelin, GHRP-6, GHRP-2 and hexarelin. They vary a lot in selectivity. Older compounds like GHRP-6 are known for strong off-target effects such as appetite signalling, whereas ipamorelin is studied specifically because it is one of the more selective, cleaner options.

Why the two families are often combined

Here is the part that ties everything together. Because GHRH analogues and ghrelin mimetics act on two separate receptors, researchers frequently pair one from each family. The logic is that two different signals arriving at the pituitary probe complementary pathways, which is more informative than doubling up on a single mechanism. The classic example is CJC-1295 combined with ipamorelin: a GHRH analogue plus a selective ghrelin mimetic.

Where MK-677 fits

You will sometimes see MK-677 (ibutamoren) listed alongside these. It is also a ghrelin-receptor agonist, so mechanistically it belongs with the GHRP family, but it is an orally active non-peptide small molecule rather than an injectable peptide. That is a useful reminder that “secretagogue” describes a mechanism, not a single chemical class.

Why not just use growth hormone directly?

It is a fair question. The research interest in secretagogues comes precisely from the fact that they work with the body’s own regulatory system rather than overriding it. Supplied growth hormone is a constant external input, whereas a secretagogue prompts the pituitary to release GH in its natural pulsatile rhythm and remains subject to the body’s feedback controls. For anyone studying how the growth-hormone axis is regulated, that indirect, pulse-preserving action is the whole appeal, and it is why the class has become such a large research area in its own right.

The takeaway

Two families, two receptors: GHRH analogues on one side, ghrelin mimetics on the other. Most research configurations combine one of each. If you can place a compound into its family, most of the confusing naming resolves itself. Our peptide guide defines the supporting terms if you want the fundamentals first.

Buy CJC-1295 + Ipamorelin in Canada

LYFE Science carries the classic pairing, CJC-1295 (No DAC) + Ipamorelin, in our signalling research category. We ship Canada-wide by Canada Post with flat $25 shipping and free delivery over $150, same-day dispatch on orders paid before noon ET, and 1 to 3 business days to most of Canada in neutral packaging. Every lot is verified by HPLC and mass spectrometry, COA available per lot. We accept Interac e-Transfer and crypto (BTC, ETH, SOL, USDC, USDT).

Buy CJC-1295 + Ipamorelin in Canada