GHRP-6
A classic synthetic growth-hormone-releasing peptide (GHRP) that mimics ghrelin to raise the body’s own GH. It is especially noted for strongly increasing appetite, and it can also raise cortisol and prolactin. Not an approved drug.
Quick take
- What it is: one of the original synthetic growth-hormone-releasing peptides (GHRPs), mimicking ghrelin.
- What people use it for: raising natural GH — and notably, strongly stimulating appetite.
- What we actually know: it reliably raises GH short-term, but also strongly increases hunger and can raise cortisol and prolactin.
- Status: not FDA-approved and banned in competitive sport.
What it is
GHRP-6 is one of the original synthetic growth-hormone-releasing peptides (GHRPs). Like ghrelin, it acts on the GH-secretagogue receptor to stimulate the pituitary to release the body’s own growth hormone (GH).1 Together with GHRP-2 and Hexarelin, it is one of the classic peptides in this class.
GHRP-6 is especially recognised for its strong appetite-stimulating effect — generally more pronounced than with GHRP-2 — which is a direct consequence of its action on the ghrelin system.
How it works
GHRP-6 binds the ghrelin/GH-secretagogue receptor and triggers a pulse of GH release, raising IGF-1.1,2 Because it works through the ghrelin pathway rather than the GHRH pathway, it is mechanistically complementary to GHRH analogues such as sermorelin or CJC-1295 and is sometimes discussed in combination with them. Its ghrelin-receptor activity also drives the marked increase in hunger that characterizes it.
What the evidence shows
Animal & mechanistic studies
Preclinical studies established GHRP-6’s GH-releasing activity and its strong ghrelin-like effect on appetite.2
Human studies
Short-term human studies confirm that GHRP-6 raises GH and stimulates appetite, along with increases in cortisol and prolactin.3 There are no long-duration outcome trials establishing benefit for recovery, body composition or aging, and long-term safety is not characterized. Popular use rests on short-term physiology plus anecdote.
Dosages reported in the literature
Informational only. The figures below describe doses reported in research and clinical settings. They are not a recommendation or a prescription, and appropriate use should be determined by a qualified healthcare professional who can account for your individual situation.
| Setting | Route | Reported range |
|---|---|---|
| Research | Subcutaneous / IV | Microgram-per-kilogram amounts as single or short-term doses |
| Anecdotal / clinic-reported | Subcutaneous | Commonly ~100–300 mcg per dose, one to several times daily |
Reported protocols vary between sources and are not supported by long-term outcome trials.
Safety & side effects
The most distinctive reported effect is a strong increase in appetite. Other reported short-term side effects include injection-site reactions, flushing, headache, water retention and elevations in cortisol and prolactin.3 Because there are no long-term controlled human studies of the popular uses, the long-term risk profile is not well characterized.
As with all peptides from the unregulated market, product purity and dose accuracy vary between sources.
Legal & regulatory status
GHRP-6 is not approved by the FDA for any use. It is banned in competitive sport — the World Anti-Doping Agency prohibits growth-hormone secretagogues at all times (category S2).4 Rules vary by country and change over time.
References
- Berlanga-Acosta J, Abreu-Cruz A, Garcia-Del Barco Herrera D, et al. Synthetic Growth Hormone-Releasing Peptides (GHRPs): A Historical Appraisal of the Evidences Supporting Their Cytoprotective Effects. Clin Med Insights Cardiol. 2017;11:1179546817694558. [PMID 28469491, doi:10.1177/1179546817694558]
- Frieboes RM, Murck H, Maier P, Schier T, Holsboer F, Steiger A. Growth hormone-releasing peptide-6 stimulates sleep, growth hormone, ACTH and cortisol release in normal man. Neuroendocrinology. 1995;61(5):584-589. | For the appetite/orexigenic mechanism: Laferrère B, Abraham C, Russell CD, Bowers CY. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. J Clin Endocrinol Metab. 2005;90(2):611-614. [PMID 7617137, PMID 15699539, doi:10.1159/000126883, doi:10.1210/jc.2004-1719]
- Frieboes RM, Murck H, Antonijevic IA, Steiger A. Effects of growth hormone-releasing peptide-6 on the nocturnal secretion of GH, ACTH and cortisol and on the sleep EEG in man: role of routes of administration. J Neuroendocrinol. 1999;11(6):473-478. | Appetite in humans: Laferrère B, Abraham C, Russell CD, Bowers CY. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. J Clin Endocrinol Metab. 2005;90(2):611-614. [PMID 10336729, PMID 15699539, doi:10.1046/j.1365-2826.1999.00364.x, doi:10.1210/jc.2004-1719]
- World Anti-Doping Agency. The Prohibited List — International Standard, Section S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics). GH-releasing peptides (GHRPs) listed include GHRP-6. Prohibited at all times. [wada-ama.org, wada-ama.org]