A plain-language, continually updated guide from Dr. Matt Chalmers’ clinical reference on hormones and peptides.
Ghrelin is a hormone produced primarily by your stomach, rising before meals and falling after eating — it’s one of your body’s primary hunger signals. It’s also directly relevant to some of our most-used peptide protocols, since compounds like Ipamorelin and Hexarelin work by activating the exact same receptor (called GHSR-1a) that ghrelin itself activates, which is how they trigger growth hormone release.
The ghrelin receptor sends its signal through a completely different internal pathway than the GHRH receptor (used by Sermorelin), which is exactly why the two are so often combined in a protocol: one primes the pituitary, and the other triggers release through a separate route, producing a stronger, more coordinated growth hormone pulse together than either compound alone. It’s also worth knowing that because this is the body’s genuine hunger-signaling pathway, peptides that activate it can noticeably increase appetite — useful for someone working on lean mass, but worth planning around if the goal is fat loss.
Ghrelin itself is not administered as a drug therapy in this practice; it’s discussed here for its physiological relevance to our GHSR-1a-targeting peptide protocols (Ipamorelin and Hexarelin) — see each of those pages for their specific research and regulatory status.
Ghrelin’s documented role as a hunger-signaling hormone is relevant to understanding appetite regulation generally. It’s not administered as a therapy in this practice; it’s discussed here because peptides like Ipamorelin and Hexarelin work by activating the same receptor ghrelin activates, and understanding that connection helps explain why those peptides can increase appetite as a side effect.
The ghrelin receptor (GHSR-1a) uses a different internal signaling pathway than the GHRH receptor, which is the specific reason combining a GHRH peptide with a ghrelin-receptor peptide produces a stronger, more coordinated GH pulse than either alone.
Peptides that share ghrelin’s receptor: Ipamorelin and Hexarelin. Also see Growth Hormone & IGF-1.
This page draws on The Pillars Path: A Root-Cause Guide to Hormones, Peptides, and Metabolic Health by Dr. Matt Chalmers — Pillars of Wellness’ clinical reference on hormone and peptide therapy.
