GHRP-6
Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Novel hexarelin analogs stimulate feeding in the rat through a mechanism not involving growth hormone release.
Torsello. A A; Luoni. M M; Schweiger. F F; Grilli. R R; Guidi. M M; Bresciani. E E; Deghenghi. R R; Müller. E E EE; Locatelli. V V
Key Findings
- Both GHRP-6 and hexarelin increase food intake and growth hormone release in rats when given subcutaneously.
- Some newly designed analogs of hexarelin affect only growth hormone release or only feeding behavior, showing the two effects can be separated.
- Minor structural tweaks to the peptide cause big shifts in whether it acts as an orexigenic (appetite‑stimulating) agent or a GH secretagogue.
Practical Outcomes
- For biohackers, GHRP-6 can be used as an appetite stimulant independent of its GH‑boosting action, which might help with weight gain or metabolic experiments. However, the data are from rats, so human effects and safety are not confirmed. If you’re interested in separating GH effects from appetite, look for analogs that have been chemically tweaked to favor one outcome over the other.
Summary
The study shows that GHRP-6 and a similar peptide called hexarelin make rats eat more, and this appetite‑boosting effect happens even when they don't cause a rise in growth hormone. Small changes to the peptide’s structure can flip whether it mainly raises growth hormone or just makes you hungry.
Abstract
Growth hormone-releasing peptides (GHRPs) are a class of small peptides that stimulate growth hormone (GH) release in several animal species, including the human. Moreover, GHRPs injected into the brain ventricles stimulate feeding in the rat. The aim of this study was to evaluate the GH-releasing properties of a series of novel GHRP analogs and the possible existence of functional correlations between the GH-releasing activity and the effects on feeding behavior. Two well-known hexapeptides, GHRP-6 and hexarelin, given s.c., dose dependently stimulated both GH release and feeding behavior in satiated rats. However, in a series of tri-, penta- and hexapeptide analogs of hexarelin, some compounds were active either on GH release or on eating behavior. Interestingly, even minor structural modifications resulted in major changes of the pharmacological profile. We conclude that GHRPs have orexigenic properties after systemic administration which are largely independent from the effects they exert on GH release.
Study Information
pubmed
1998
1998-11-06T00:00:00.000Z
10.1016/s0014-2999(98)00677-3