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.

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.