Research Only Growth Hormone Axis

GHRP-6

also known as: Growth Hormone Releasing Peptide 6, SKF-110679

The prototype GHRP — a hexapeptide ghrelin receptor agonist notable for pronounced hunger stimulation and less favorable cortisol/prolactin profile than newer GHRPs.

The original growth hormone-releasing peptide hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2), discovered by Bowers in the 1980s and the template from which all later GHRPs and ipamorelin were derived.

Mechanism of action

Agonist at GHS-R1a (ghrelin receptor). Stimulates pulsatile GH release and, unlike ipamorelin, produces a pronounced appetite-stimulating effect via hypothalamic ghrelin signaling — making it a GH secretagogue with an unusual "hunger" signature. Cortisol and prolactin effects are more pronounced than with ipamorelin.

Primary uses

Ghrelin receptor research
Historical GH-axis research
Community GH stacks (less common than ipamorelin)

Typical dosing

100–300 mcg 2–3 times daily (subcutaneous)

Community dosing only.

→ Full GHRP-6 dosage guide — community ranges, its pronounced appetite-stimulating effect, how it compares to GHRP-2 and ipamorelin, and unapproved status.

Regulatory status

Not approved in any major jurisdiction. Historical research compound and now a research-chemical channel product.

References

[pubmed] Bowers CY, et al. "On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone." Endocrinology, 1984;114:1537-1545.
[review] Camanni F, et al. "Growth hormone-releasing peptides and their analogs." Front Neuroendocrinol, 1998;19:47-72.

Related peptides

Ipamorelin

A selective ghrelin receptor agonist that stimulates GH release without the cortisol, prolactin, or ACTH spike seen with older GHRPs like GHRP-6.

GHRP-2

A second-generation GHRP approved as a diagnostic agent in Japan, with more pronounced GH-releasing potency than GHRP-6 but a meaningful prolactin and cortisol rise at higher doses.

Hexarelin

A high-potency GHRP studied for cardiac protection via a CD36-mediated pathway independent of GH release — but demonstrates clear tachyphylaxis with chronic use.

CJC-1295

A long-acting GHRH analog engineered with a DAC linker that binds serum albumin, extending half-life from minutes to approximately 8 days.

Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.