GHRP-6
Growth hormone releasing peptide-6, SKF-110679
The oldest of the growth hormone releasing peptides and the hungriest. The appetite stimulation is not a side effect people tolerate, it is the reason some of them take it.
Preclinical only
Not approved anywhere for any indication. Sold as research material. Cuban research groups have pursued it for cardiac and tissue-protective indications without producing an approval.
What it is
GHRP-6 is the original synthetic growth hormone releasing peptide, developed in the 1980s from work on opioid-derived peptides that unexpectedly triggered growth hormone release. It led directly to the discovery of the ghrelin receptor, which was named after the natural ligand found afterwards.
It is a hexapeptide that binds that receptor and produces a strong growth hormone pulse. It also produces a strong hunger signal, because that receptor's natural job is signalling hunger.
The appetite effect is the whole personality of this compound
Ghrelin is the hormone that tells you to eat. GHRP-6 is a potent agonist at its receptor, and the hunger arrives within minutes and is frequently described as difficult to ignore.
For most people that rules it out, and GHRP-2 or ipamorelin get chosen instead precisely to avoid it. For someone trying to eat through a bulking phase or struggling with appetite, it is the point of using this one rather than a cleaner alternative.
Either way it should be a deliberate choice. People who buy GHRP-6 without knowing this consistently report being ambushed by it.
What the evidence supports, and what it does not
The growth hormone release is real and demonstrated in humans. Everything beyond that is preclinical.
Cuban research groups have published a substantial body of animal work on GHRP-6 for cardioprotection and tissue protection, including recent models of post-infarct ventricular remodelling and lung injury. It is genuinely interesting biology and it is rodent biology. No completed randomised human trial supports any therapeutic use, which is why this entry sits a tier below GHRP-2.
Practical notes
- Selectivity is the worst in the class. Cortisol and prolactin both rise more than with ipamorelin or GHRP-2. If the goal is growth hormone specifically, this is the least targeted way to get it.
- Food blunts it. A meal before injection reduces the growth hormone response noticeably, which is why reported protocols call for an empty stomach either side of the dose. That instruction collides awkwardly with a compound that makes you ravenous.
- It is the historically important one, not the practically best one. GHRP-6 is why we know about the ghrelin receptor. That does not make it the compound to choose in 2026.
Side effects and warning signs
Commonly reported
- Intense hunger within minutes of injection, the defining feature of this compound
- Water retention
- Raised cortisol and prolactin, the worst of the commonly used secretagogues on this measure
- Head rush or flushing shortly after dosing
- Tingling or numbness in the hands
Stop and get medical help
- Any active malignancy
- Persistent numbness in the hands suggesting carpal tunnel
- Rising fasting glucose
Sources
From the community
Discussion for this compound concentrates in r/Peptides.
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