Growth Hormone Research Peptides: A Canadian Guide
The growth hormone axis is a tightly regulated signaling system, and the peptides studied around it act at several different points along that pathway. This guide organizes the main growth-hormone research compounds available to Canadian laboratories by where they act: the GHRH analogs that prompt the pituitary to release growth hormone, the ghrelin-receptor secretagogues that trigger release through a separate receptor, the downstream IGF-1 family that carries out many of growth hormone's effects, and recombinant growth hormone itself. Knowing which point of the axis a compound targets is the key to reading the research literature around it.
Growth hormone is released from the pituitary in pulses, under the opposing control of GHRH, which stimulates release, and somatostatin, which suppresses it. Once in circulation, growth hormone acts partly through insulin-like growth factor 1, or IGF-1, produced mainly in the liver. The compounds below map onto this cascade, and the table groups them by category.
| Category | Compound | Mechanism | Research focus |
|---|---|---|---|
| GHRH analogs | Sermorelin | GHRH(1-29) receptor agonist | Endogenous GH release, short half-life |
| GHRH analogs | Tesamorelin | Stabilized GHRH analog | GH axis and visceral adipose research |
| GHRH analogs | CJC-1295 with Ipamorelin | Long-acting GHRH analog blend | Sustained GH pulse research |
| Ghrelin-receptor secretagogues | Ipamorelin | Selective GHS-R1a agonist | Selective GH release |
| Ghrelin-receptor secretagogues | GHRP-2 | GHS-R1a agonist | GH release research |
| Ghrelin-receptor secretagogues | GHRP-6 | GHS-R1a agonist | GH release and appetite signaling |
| Ghrelin-receptor secretagogues | Hexarelin | Potent GHS-R1a agonist | GH secretagogue research |
| IGF-1 family | IGF-1 LR3 | Long Arg3 IGF-1 analog | IGF-1 receptor and cell growth |
| IGF-1 family | PEG-MGF | Pegylated mechano growth factor | Muscle repair and satellite cells |
| Recombinant GH | HGH 191aa Somatropin | Recombinant human growth hormone | Full-length GH reference research |
GHRH analogs
Sermorelin is a truncated GHRH analog consisting of the first 29 amino acids of growth-hormone-releasing hormone, the minimum sequence needed to activate the GHRH receptor. It has a very short circulating half-life, on the order of minutes, and research has used it as a tool to probe pituitary responsiveness and endogenous growth hormone release. The growth-hormone axis overview places it alongside the other secretagogues.
Tesamorelin is a stabilized GHRH analog engineered for greater metabolic stability than sermorelin. Its research profile is notable for work on visceral adipose tissue, and it is one of the more thoroughly studied compounds in this group. A direct comparison with a ghrelin-receptor agonist is available in the ipamorelin and tesamorelin comparison.
CJC-1295 with Ipamorelin is a combination preparation that pairs the long-acting GHRH analog CJC-1295 with the selective secretagogue ipamorelin. The pairing is studied because the two act on different receptors - GHRH and ghrelin - and researchers use it to examine how combined stimulation shapes the growth hormone pulse.
Ghrelin-receptor secretagogues
Ipamorelin is a selective agonist of the growth hormone secretagogue receptor GHS-R1a, the same receptor that the hunger hormone ghrelin binds. It is valued in research for its selectivity, prompting growth hormone release with comparatively little effect on cortisol or prolactin in the models studied. GHRP-2 and GHRP-6 are earlier growth-hormone-releasing peptides that act on the same receptor; GHRP-6 is additionally noted in the literature for its pronounced effect on appetite signaling, while GHRP-2 is often described as the more potent releaser of the two.
Hexarelin is another GHS-R1a agonist and one of the most potent of the classic growth-hormone-releasing peptides, studied both for growth hormone release and for receptor-desensitization behavior under repeated exposure in preclinical models.
The IGF-1 family and recombinant GH
IGF-1 LR3 is a modified form of insulin-like growth factor 1 - Long Arg3 IGF-1 - carrying an extended amino-terminal sequence and an arginine substitution that reduce its binding to IGF binding proteins. The result is a substantially longer active window than native IGF-1, which is why research uses it to study IGF-1 receptor signaling and cell growth. PEG-MGF is a pegylated form of mechano growth factor, a splice variant of IGF-1 expressed in mechanically stressed muscle; the polyethylene glycol group improves its stability, and it has been examined in muscle-repair and satellite-cell research.
HGH 191aa Somatropin is recombinant human growth hormone itself, the full 191-amino-acid sequence produced through recombinant technology. Rather than prompting the pituitary to release more of its own growth hormone, it supplies the intact molecule directly, and it serves as a reference point against which the secretagogues above are compared.
Handling notes
These compounds are supplied as lyophilized powder and reconstituted with bacteriostatic water for laboratory measurement. The peptides are generally stored frozen as powder and refrigerated once dissolved, kept protected from light. To review current Canadian stock, vial sizes, and certificates of analysis, browse the store.
Research use only. This article is educational and is not medical, legal, or financial advice. The compounds discussed are not approved for human or veterinary use, consumption, or therapeutic application.