What it is
GHRP-6 is a peptide made of 6 amino acids. It is made in a lab. Cyril Bowers and his team built it in the 1980s. It was the first peptide ever made that releases growth hormone. It attaches to the ghrelin receptor. Ghrelin is the hunger hormone, but ghrelin was not discovered until 1999. GHRP-6 proved the receptor existed 15 years before anyone found the hormone that fits it. Along with growth hormone, GHRP-6 raises hunger, cortisol, and prolactin. Other names: Growth Hormone Releasing Peptide 6, Growth Hormone Releasing Hexapeptide.
What researchers study it for
- Growth hormone release in animals and people
- Hunger and feeding behavior in animals
- Gut movement
- Heart protection after heart attack in pigs
- As the baseline that newer peptides in this class are compared against
What the studies found
1. It made rats eat more, even with no rise in growth hormone.
A 1995 study injected GHRP-6 straight into rat brains. The rats ate more. Their growth hormone did not rise. This proved the hunger effect and the growth hormone effect are two separate actions in two separate places. It also pointed researchers toward a hunger hormone that had not been found yet. That hormone turned out to be ghrelin.
2. It cut heart damage by 78 percent in pigs after a heart attack.
A 2007 study blocked a heart artery in pigs for one hour, then treated them with GHRP-6 or salt water. The dead area of heart muscle was 78 percent smaller in treated pigs. Blood markers of heart damage were lower. The protection came from lower oxidative stress, not from IGF-1 or growth hormone. Pig data only. No human heart trial exists.
3. It works on two parts of the brain at once.
A 1998 review by Bowers, who built GHRP-6, explains that this class acts on both the hypothalamus and the pituitary. Those are the two brain structures that control growth hormone. That two-point action is why GHRP-6 and GHRH together release far more growth hormone than either one alone.
4. It raises cortisol and ACTH along with growth hormone.
The 1998 study that introduced ipamorelin tested GHRP-6 side by side with it in rats and pigs. GHRP-6 raised the stress hormones cortisol and ACTH at growth hormone releasing doses. Ipamorelin did not. This is why researchers who want to study growth hormone alone moved to ipamorelin, and why GHRP-6 is now used mostly for hunger and heart research.
How much research exists
Many animal and human studies going back to the 1980s. It was never taken through drug approval. Today it is used mostly as the reference compound that newer peptides in this class are measured against.
Facts
- Formula: C46H56N12O6
- Weight: 873.0 g/mol
- CAS number: 87616-84-0
- Sequence: His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
- Time in the blood: 15 to 60 minutes
- Storage: freeze the dry powder. Keep mixed solution in the fridge.
Legal status
Not approved by the FDA or any other agency for human use. Banned in sports by WADA under section S2.
For research use only. Not for human use. Nothing here is medical advice.