GHRP-6

GHRP-6 is the molecule that gave the whole growth hormone releasing peptide family its name. Cyril Y. Bowers and colleagues at Tulane University reported the hexapeptide in 1984, building on the enkephalin work that had hinted a non-GHRH route to growth hormone release was possible. The sequence is His-D-Trp-Ala-Trp-D-Phe-Lys-NH2, six residues with two D-amino acids for proteolytic stability, and it became the reference compound every later GHRP was measured against in pituitary cell assays.

The 1984 hexapeptide that named the family

Before GHRP-6 there was no GHRP class. Bowers had been chasing the active fragment for years, and the 1984 hexapeptide was the first synthetic ligand that released growth hormone reliably in vitro and in vivo through a receptor that was not the GHRH receptor. That orphan receptor was eventually identified in 1996 and renamed the ghrelin receptor (GHS-R1a) when the endogenous ligand was found in 1999. For literature searches, GHRP-6 is the entry point: most receptor characterisation papers from the 1990s used it as the prototypical agonist.

SKF-110679 and the SmithKline paper trail

SmithKline Beecham picked up GHRP-6 for clinical investigation under the internal development code SKF-110679. Pharmacology references and old patent filings will list both names interchangeably. If a paper cites SKF-110679 and you cannot place the compound, it is the same hexapeptide on your vial. The CAS number for the acetate salt is 87616-84-0, and molecular weight runs at 872.4 g/mol for the free base.

The hunger signal that sets it apart

Among the GHRPs, GHRP-6 is the one that consistently produces a marked feeding response in rodent models, generally read as ghrelin-receptor activation feeding into hypothalamic NPY and AgRP neurons. Later peptides in the family, including GHRP-2 and Ipamorelin, were partly designed to dial that effect down while keeping GH release intact. For appetite and energy-balance researchers, that is the reason GHRP-6 still has a place on the bench even with newer secretagogues available. The same effect is why direct comparison studies almost always include GHRP-6 as the positive feeding control.

Sequence, receptor, and where it stops

GHRP-6 binds GHS-R1a on pituitary somatotrophs and on hypothalamic neurons. It has no measurable affinity for the GHRH receptor, which is the cleanest way to separate it from peptides like Sermorelin or CJC-1295. Reported acute effects in animal work include amplified GH pulses, a transient appetite spike, and modest changes in gastric motility. Cortisol and prolactin responses are present but generally smaller than those reported for Hexarelin in matched protocols.

On the QC bench before it leaves

Each vial holds lyophilised GHRP-6 acetate, synthesised through UK and EU peptide manufacturers we work with directly rather than relabelled stock from open marketplaces. Every batch is released against HPLC for purity and mass spectrometry for identity, and the CoA tied to the lot number on your vial can be pulled on live chat before or after the order. If any vial fails to match its CoA on independent testing, the order is refunded in full.

UK dispatch, chat, and tiered pricing

About nine in ten UK orders ship and arrive inside 48 hours. Live chat is staffed in UK hours by people who can read batch documentation while you are on the line. For studies needing ten vials or more, contact support for tiered pricing rather than stacking the cart at the listed unit price.

Sold strictly for in vitro laboratory research. Not for human or veterinary use. UK 18+.